1
|
Jamwal P, Ahuja R, Kumar R. Van Hove singularity driven enhancement of superconductivity in two-dimensional tungsten monofluoride (WF). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:245001. [PMID: 38411011 DOI: 10.1088/1361-648x/ad2d47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 02/26/2024] [Indexed: 02/28/2024]
Abstract
Superconductivity in two-dimensional materials has gained significant attention in the last few years. In this work, we report phonon-mediated superconductivity investigations in monolayer Tungsten monofluoride (WF) by solving anisotropic Migdal Eliashberg equations as implemented in EPW. By employing first-principles calculations, our examination of phonon dispersion spectra suggests that WF is dynamically stable. Our results show that WF has weak electron-phonon coupling (EPC) strength (λ) of 0.49 with superconducting transition temperature (Tc) of 2.6 K. A saddle point is observed at 0.11 eV below the Fermi level (EF) of WF, which corresponds to the Van Hove singularity (VHS). On shifting the Fermi level to the VHS by hole doping (3.7 × 1014cm-2), the EPC strength increases to 0.93, which leads to an increase in theTcto 11 K. However, the superconducting transition temperature of both pristine and doped WF increases to approximately 7.2 K and 17.2 K, respectively, by applying the Full Bandwidth (FBW) anisotropic Migdal-Eliashberg equations. Our results provide a platform for the experimental realization of superconductivity in WF and enhancement of the superconducting transition temperature by adjusting the position ofEFto the VHS.
Collapse
Affiliation(s)
- Prarena Jamwal
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| | - Rajeev Ahuja
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
- Condensed Matter Theory Group, Department of Physics and Astronomy, Uppsala University, Box 516, Uppsala 75120, Sweden
| | - Rakesh Kumar
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar 140001, Punjab, India
| |
Collapse
|
2
|
Shi X, Gao J, Qiu S, Chang Y, Zhao L, Fu ZG, Zhao J, Zhang P. Stability and superconductivity of freestanding two-dimensional transition metal boridene: M 4/3B 2. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 36:085602. [PMID: 37939399 DOI: 10.1088/1361-648x/ad0ace] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 11/08/2023] [Indexed: 11/10/2023]
Abstract
The small atomic mass of boron indicates strong electron-phonon coupling (EPC), so it may have a brilliant performance in superconductivity. Recently, a new 2D boride sheet with ordered metal vacancies and surface terminals (Mo4/3B2-x) was realized in experiments (Zhouet al2021Science373801). Here, the 2D monolayer freestanding Mo4/3B2is evidenced to be thermodynamically stable. Through electronic structure, phonon spectrum and EPC, monolayer Mo4/3B2is found to be an intrinsic phonon-mediated superconductor. The superconducting transition temperature (Tc) is determined to be 4.06 K by the McMillian-Allen-Dynes formula. Remarkably, theTcof monolayer Mo4/3B2can be increased to 6.78 K with an appropriate biaxial tensile strain (+5%). Moreover, we predict that other transition metal replacing Mo atoms is also stable and retaining the superconductivity. Such as monolayer W4/3B2is also a superconductor with theTcof 2.37 K. Our research results enrich the database of 2D monolayer superconductors and boron-related formed materials science.
Collapse
Affiliation(s)
- Xiaoran Shi
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People's Republic of China
| | - Junfeng Gao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People's Republic of China
| | - Shi Qiu
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People's Republic of China
| | - Yuan Chang
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People's Republic of China
| | - Luneng Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People's Republic of China
| | - Zhen-Guo Fu
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, People's Republic of China
| | - Jijun Zhao
- Key Laboratory of Materials Modification by Laser, Ion and Electron Beams, Dalian University of Technology, Ministry of Education, Dalian 116024, People's Republic of China
| | - Ping Zhang
- Institute of Applied Physics and Computational Mathematics, Beijing 100088, People's Republic of China
| |
Collapse
|
3
|
Ao L, Huang J, Qin F, Li Z, Ideue T, Akhtari K, Chen P, Bi X, Qiu C, Huang D, Chen L, Belosludov RV, Gou H, Ren W, Nojima T, Iwasa Y, Bahramy MS, Yuan H. Valley-dimensionality locking of superconductivity in cubic phosphides. SCIENCE ADVANCES 2023; 9:eadf6758. [PMID: 37683003 PMCID: PMC10491139 DOI: 10.1126/sciadv.adf6758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 08/08/2023] [Indexed: 09/10/2023]
Abstract
Two-dimensional superconductivity is primarily realized in atomically thin layers through extreme exfoliation, epitaxial growth, or interfacial gating. Apart from their technical challenges, these approaches lack sufficient control over the Fermiology of superconducting systems. Here, we offer a Fermiology-engineering approach, allowing us to desirably tune the coherence length of Cooper pairs and the dimensionality of superconducting states in arsenic phosphides AsxP1-x under hydrostatic pressure. We demonstrate how this turns these compounds into tunable two-dimensional superconductors with a dome-shaped phase diagram even in the bulk limit. This peculiar behavior is shown to result from an unconventional valley-dimensionality locking mechanism, driven by a delicate competition between three-dimensional hole-type and two-dimensional electron-type energy pockets spatially separated in momentum space. The resulting dimensionality crossover is further discussed to be systematically controllable by pressure and stoichiometry tuning. Our findings pave a unique way to realize and control superconducting phases with special pairing and dimensional orders.
Collapse
Affiliation(s)
- Lingyi Ao
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Junwei Huang
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Feng Qin
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Zeya Li
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Toshiya Ideue
- Quantum-Phase Electronic Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- Institute for Solid State Physics, The University of Tokyo, Chiba 277-8581, Japan
| | - Keivan Akhtari
- Department of Physics, University of Kurdistan, Sanandaj 416, Iran
| | - Peng Chen
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Xiangyu Bi
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Caiyu Qiu
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| | - Dajian Huang
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
| | - Long Chen
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | | | - Huiyang Gou
- Center for High Pressure Science and Technology Advanced Research, Beijing 100094, China
| | - Wencai Ren
- Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Tsutomu Nojima
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - Yoshihiro Iwasa
- Quantum-Phase Electronic Center and Department of Applied Physics, The University of Tokyo, Tokyo 113-8656, Japan
- RIKEN Center for Emergent Matter Science, Wako, Saitama 351-0198, Japan
| | - Mohammad Saeed Bahramy
- Department of Physics and Astronomy, School of Natural Sciences, The University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Hongtao Yuan
- National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210000, China
| |
Collapse
|
4
|
Averyanov DV, Sokolov IS, Parfenov OE, Taldenkov AN, Karateev IA, Kondratev OA, Tokmachev AM, Storchak VG. Thickness-Dependent Superconductivity in a Layered Electride on Silicon. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2302065. [PMID: 37259278 DOI: 10.1002/smll.202302065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 05/04/2023] [Indexed: 06/02/2023]
Abstract
Layered materials exhibit a plethora of fascinating properties. The challenge is to make the materials into epitaxial films, preferably integrated with mature technological platforms to facilitate their potential applications. Progress in this direction can establish the film thickness as a valuable parameter to control various phenomena, superconductivity in particular. Here, a synthetic route to epitaxial films of SrAlSi, a layered superconducting electride, on silicon is designed. A set of films ranging in thickness is synthesized employing a silicene-based template. Their structure and superconductivity are explored by a combination of techniques. Two regimes of TC dependence on the film thickness are identified, the coherence length being the crossover parameter. The results can be extended to syntheses of other honeycomb-lattice ternary compounds on Si or Ge exhibiting superconducting, magnetic, and other properties.
Collapse
Affiliation(s)
- Dmitry V Averyanov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Ivan S Sokolov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Oleg E Parfenov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Alexander N Taldenkov
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Igor A Karateev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Oleg A Kondratev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Andrey M Tokmachev
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| | - Vyacheslav G Storchak
- National Research Center "Kurchatov Institute", Kurchatov Sq. 1, Moscow, 123182, Russia
| |
Collapse
|
5
|
Aydin A, Sisman A. Origin of the quantum shape effect. Phys Rev E 2023; 108:024105. [PMID: 37723725 DOI: 10.1103/physreve.108.024105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 07/12/2023] [Indexed: 09/20/2023]
Abstract
The quantum size and shape effects are often considered difficult to distinguish from each other because of their coexistence. Essentially, it is possible to separate them and focus solely on the shape effect by considering a size-invariant shape transformation, which changes the discrete energy spectra of strongly confined systems and causes the quantum shape effects. The size-invariant shape transformation is a geometric technique of transforming shapes by preserving the boundary curvature, topology, and the Lebesgue measure of a bounded domain. The quantum shape effect is a quite different phenomenon from quantum size effects, as it can have the opposite influence on the physical properties of nanoscale systems. While quantum size effects can usually be obtained via bounded continuum approximation, the quantum shape effect is a direct consequence of the energy quantization in specifically designed confined geometries. Here, we explore the origin of the quantum shape effect by theoretically investigating the simplest system that can produce the same physics: quantum particles in a one-dimensional box separated by a moving partition. The partition moves quasistatically from one end of the box to the other, allowing the system to remain in equilibrium with a reservoir throughout the process. The partition and the boundaries are impenetrable by particles, forming two effectively interconnected regions. The position of the partition becomes the shape variable. We investigate the quantum shape effect on the thermodynamic properties of confined particles considering their discrete spectrum. In addition, we applied an analytical model based on dimensional transitions to predict thermodynamic properties under the quantum shape effect accurately. A fundamental understanding of quantum shape effects could pave the way for employing them to engineer physical properties and design better materials at the nanoscale.
Collapse
Affiliation(s)
- Alhun Aydin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
- Department of Physics, Koç University, 34450 Sarıyer, Istanbul, Turkey
| | - Altug Sisman
- Department of Physics and Astronomy, Uppsala University, 75120 Uppsala, Sweden
| |
Collapse
|
6
|
Zhou K, Shang G, Hsu HH, Han ST, Roy VAL, Zhou Y. Emerging 2D Metal Oxides: From Synthesis to Device Integration. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207774. [PMID: 36333890 DOI: 10.1002/adma.202207774] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/26/2022] [Indexed: 05/26/2023]
Abstract
2D metal oxides have aroused increasing attention in the field of electronics and optoelectronics due to their intriguing physical properties. In this review, an overview of recent advances on synthesis of 2D metal oxides and their electronic applications is presented. First, the tunable physical properties of 2D metal oxides that relate to the structure (various oxidation-state forms, polymorphism, etc.), crystallinity and defects (anisotropy, point defects, and grain boundary), and thickness (quantum confinement effect, interfacial effect, etc.) are discussed. Then, advanced synthesis methods for 2D metal oxides besides mechanical exfoliation are introduced and classified into solution process, vapor-phase deposition, and native oxidation on a metal source. Later, the various roles of 2D metal oxides in widespread applications, i.e., transistors, inverters, photodetectors, piezotronics, memristors, and potential applications (solar cell, spintronics, and superconducting devices) are discussed. Finally, an outlook of existing challenges and future opportunities in 2D metal oxides is proposed.
Collapse
Affiliation(s)
- Kui Zhou
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Gang Shang
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Hsiao-Hsuan Hsu
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei, 10608, Taiwan
| | - Su-Ting Han
- College of Electronics and Information Engineering, Shenzhen University, Shenzhen, 518060, P. R. China
| | - Vellaisamy A L Roy
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Ye Zhou
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, P. R. China
| |
Collapse
|
7
|
van Weerdenburg WM, Kamlapure A, Fyhn EH, Huang X, van Mullekom NP, Steinbrecher M, Krogstrup P, Linder J, Khajetoorians AA. Extreme enhancement of superconductivity in epitaxial aluminum near the monolayer limit. SCIENCE ADVANCES 2023; 9:eadf5500. [PMID: 36857452 PMCID: PMC9977180 DOI: 10.1126/sciadv.adf5500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
BCS theory has been widely successful at describing elemental bulk superconductors. Yet, as the length scales of such superconductors approach the atomic limit, dimensionality as well as the environment of the superconductor can lead to drastically different and unpredictable superconducting behavior. Here, we report a threefold enhancement of the superconducting critical temperature and gap size in ultrathin epitaxial Al films on Si(111), when approaching the 2D limit, based on high-resolution scanning tunneling microscopy/spectroscopy (STM/STS) measurements. Using spatially resolved spectroscopy, we characterize the vortex structure in the presence of a strong Zeeman field and find evidence of a paramagnetic Meissner effect originating from odd-frequency pairing contributions. These results illustrate two notable influences of reduced dimensionality on a BCS superconductor and present a platform to study BCS superconductivity in large magnetic fields.
Collapse
Affiliation(s)
| | - Anand Kamlapure
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | - Eirik Holm Fyhn
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | - Xiaochun Huang
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | | | - Manuel Steinbrecher
- Institute for Molecules and Materials, Radboud University, 6525 AJ Nijmegen, Netherlands
| | - Peter Krogstrup
- NNF Quantum Computing Programme, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Jacob Linder
- Center for Quantum Spintronics, Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway
| | | |
Collapse
|
8
|
Er-Rahmany S, Loulidi M, El Kenz A, Benyoussef A, Balli M, Azzouz M. Prediction of superconductivity in Li, K, Ca, and Sr-intercalated blue phosphorene bilayer using first-principle calculations. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:135601. [PMID: 36693282 DOI: 10.1088/1361-648x/acb5d9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/24/2023] [Indexed: 06/17/2023]
Abstract
Blue phosphorene is an interesting two-dimensional (2D) material, which has attracted the attention of researchers, due to its affluent physical and chemical properties. In recent years, it was discovered that the intercalation of alkali metals and alkaline earth metals in 2D materials may lead to conventional Bardeen-Cooper-Schrieffer (BCS) superconductivity. In this work, the electronic structure, phonon dispersion, Eliashberg spectral function, electron-phonon coupling (EPC), and the critical temperature of blue phosphorene bilayer intercalated by alkali metals (Li, and K) and alkaline earth metals (Ca, and Sr) for both AB and AC stacking orders are studied using the density functional theory and the density functional perturbation theory, within the generalized gradient approximation with van der Waals correction. The present work shows that the blue phosphorene bilayer is dynamically stable in AB stacking for Li and AC stacking for K, Ca, and Sr, and after intercalation, it transforms from a semiconductor to a metal owing to charge transfer between intercalated atoms and phosphorene. Furthermore, the EPC constant and the critical temperature are higher than those of 2D BCS-type superconductors. They are about 3 and 24.61 K respectively for K-intercalated blue phosphorene bilayer. Thus, our results suggest that blue phosphorene is a good candidate for a superconductor.
Collapse
Affiliation(s)
- S Er-Rahmany
- Laboratory of Condensed Matter and Interdisciplinary Sciences, Unite de Recherche Labelliseìe CNRST, URL-CNRST-17, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco
- AMEEC Team, LERMA, College of Engineering and Architecture, International University of Rabat, Parc Technopolis, Rocade de Rabat-Salé, Sala El jadida11100, Morocco
| | - M Loulidi
- Laboratory of Condensed Matter and Interdisciplinary Sciences, Unite de Recherche Labelliseìe CNRST, URL-CNRST-17, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco
| | - A El Kenz
- Laboratory of Condensed Matter and Interdisciplinary Sciences, Unite de Recherche Labelliseìe CNRST, URL-CNRST-17, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco
| | - A Benyoussef
- Laboratory of Condensed Matter and Interdisciplinary Sciences, Unite de Recherche Labelliseìe CNRST, URL-CNRST-17, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco
- Hassan II Academy of Sciences and Techniques, Rabat, Morocco
| | - M Balli
- AMEEC Team, LERMA, College of Engineering and Architecture, International University of Rabat, Parc Technopolis, Rocade de Rabat-Salé, Sala El jadida11100, Morocco
| | - M Azzouz
- Al Akhawayn University, School of Science and Engineering, PO Box 104, Hassan II Avenue, 53000 Ifrane, Morocco
| |
Collapse
|
9
|
Thedford RP, Yu F, Tait WRT, Shastri K, Monticone F, Wiesner U. The Promise of Soft-Matter-Enabled Quantum Materials. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2203908. [PMID: 35863756 DOI: 10.1002/adma.202203908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 07/14/2022] [Indexed: 06/15/2023]
Abstract
The field of quantum materials has experienced rapid growth over the past decade, driven by exciting new discoveries with immense transformative potential. Traditional synthetic methods to quantum materials have, however, limited the exploration of architectural control beyond the atomic scale. By contrast, soft matter self-assembly can be used to tailor material structure over a large range of length scales, with a vast array of possible form factors, promising emerging quantum material properties at the mesoscale. This review explores opportunities for soft matter science to impact the synthesis of quantum materials with advanced properties. Existing work at the interface of these two fields is highlighted, and perspectives are provided on possible future directions by discussing the potential benefits and challenges which can arise from their bridging.
Collapse
Affiliation(s)
- R Paxton Thedford
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, 14853, USA
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, 14853, USA
| | - Fei Yu
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, 14853, USA
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, New York, 14853, USA
| | - William R T Tait
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, 14853, USA
- Smith School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York, 14853, USA
| | - Kunal Shastri
- Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York, 14853, USA
| | - Francesco Monticone
- Department of Electrical and Computer Engineering, Cornell University, Ithaca, New York, 14853, USA
| | - Ulrich Wiesner
- Department of Materials Science and Engineering, Cornell University, Ithaca, New York, 14853, USA
| |
Collapse
|
10
|
Formation of surface states on Pb(111) by Au adsorption. Sci Rep 2023; 13:1689. [PMID: 36717611 PMCID: PMC9886988 DOI: 10.1038/s41598-023-28106-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/12/2023] [Indexed: 01/31/2023] Open
Abstract
Using low-energy electron diffraction and angle-resolved photoemission spectroscopy, we investigated the lattice and electronic structures of the Pb(111) surface upon the adsorption of Au atoms at the low temperature T = 40 K. Unlike earlier results showing the formation of PbAu-alloy layers at room temperature, we found that Au atoms form a ultra-thin superstructure, Au/Pb(111)-3 × 3, on top of the Pb(111) surface. Moreover, three surface-state bands, S1, S2, and S3, are induced within and immediately adjacent to the Pb bulk projected band gap centered at the surface zone boundary [Formula: see text] at the energies of - 0.02, - 1.05, and - 2.56 eV, respectively. First-principles calculation based on Au/Pb(111)-3 × 3 confirms the measured surface-state bands among which the most interesting are the S1 and S3 surface states. They are derived from surface resonances in Pb(111). Moreover, S1, which disperses across Fermi level, exhibits a large anisotropic Rashba splitting with α of 1.0 and 3.54 eVÅ in the two symmetry directions centered at [Formula: see text]. The corresponding Rashba splitting of S1 band in Cu/Pb(111)-3 × 3 and Ag/Pb(111)-3 × 3 were calculated for comparison.
Collapse
|
11
|
Tuning lower dimensional superconductivity with hybridization at a superconducting-semiconducting interface. Nat Commun 2022; 13:4452. [PMID: 35915086 PMCID: PMC9343457 DOI: 10.1038/s41467-022-31948-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 07/07/2022] [Indexed: 11/13/2022] Open
Abstract
The influence of interface electronic structure is vital to control lower dimensional superconductivity and its applications to gated superconducting electronics, and superconducting layered heterostructures. Lower dimensional superconductors are typically synthesized on insulating substrates to reduce interfacial driven effects that destroy superconductivity and delocalize the confined wavefunction. Here, we demonstrate that the hybrid electronic structure formed at the interface between a lead film and a semiconducting and highly anisotropic black phosphorus substrate significantly renormalizes the superconductivity in the lead film. Using ultra-low temperature scanning tunneling microscopy and spectroscopy, we characterize the renormalization of lead’s quantum well states, its superconducting gap, and its vortex structure which show strong anisotropic characteristics. Density functional theory calculations confirm that the renormalization of superconductivity is driven by hybridization at the interface which modifies the confinement potential and imprints the anisotropic characteristics of the semiconductor substrate on selected regions of the Fermi surface of lead. Using an analytical model, we link the modulated superconductivity to an anisotropy that selectively tunes the superconducting order parameter in reciprocal space. These results illustrate that interfacial hybridization can be used to tune superconductivity in quantum technologies based on lower dimensional superconducting electronics. Lower-dimensional superconductors are typically synthesized on insulating substrates. Here, the authors find that the hybrid electronic structure formed at the interface between a lead film and a semiconducting black phosphorus substrate significantly renormalizes the superconductivity in the lead film.
Collapse
|
12
|
Cucciniello N, Lee D, Feng HY, Yang Z, Zeng H, Patibandla N, Zhu M, Jia Q. Superconducting niobium nitride: a perspective from processing, microstructure, and superconducting property for single photon detectors. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:374003. [PMID: 35779516 DOI: 10.1088/1361-648x/ac7dd6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 07/01/2022] [Indexed: 06/15/2023]
Abstract
Superconducting niobium nitride (NbN) continues to be investigated decades on, largely in part to its advantageous superconducting properties and wide use in superconducting electronics. Particularly, NbN-based superconducting nanowire single-photon detectors (SNSPDs) have shown exceptional performance and NbN remains as the material of choice in developing future generation quantum devices. In this perspective, we describe the processing-structure-property relationships governing the superconducting properties of NbN films. We further discuss the complex interplay between the material properties, processing parameters, substrate materials, device architectures, and performance of SNSPDs. We also highlight the latest progress in optimizing SNSPD performance parameters.
Collapse
Affiliation(s)
- Nicholas Cucciniello
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY 14260, United States of America
| | - Derek Lee
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY 14260, United States of America
| | - Henry Y Feng
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY 14260, United States of America
| | - Zihao Yang
- Applied Materials, Inc., Santa Clara, CA 95054, United States of America
| | - Hao Zeng
- Department of Physics, University at Buffalo-The State University of New York, Buffalo, NY 14260, United States of America
| | - Nag Patibandla
- Applied Materials, Inc., Santa Clara, CA 95054, United States of America
| | - Mingwei Zhu
- Applied Materials, Inc., Santa Clara, CA 95054, United States of America
| | - Quanxi Jia
- Department of Materials Design and Innovation, University at Buffalo-The State University of New York, Buffalo, NY 14260, United States of America
| |
Collapse
|
13
|
Hot-Pressed Two-Dimensional Amorphous Metals and Their Electronic Properties. CRYSTALS 2022. [DOI: 10.3390/cryst12050616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
As an emerging research field, two-dimensional (2D) metals have been the subject of increasing research efforts in recent years due to their potential applications. However, unlike typical 2D layered materials, such as graphene, which can be exfoliated from their bulk parent compounds, it is hardly possible to produce 2D metals through exfoliation techniques due to the absence of Van der Waals gaps. Indeed, the lack of effective material preparation methods severely limits the development of this research field. Here, we report a PDMS-assisted hot-pressing method in glovebox to obtain ultraflat nanometer-thick 2D metals/metal oxide amorphous films of various low-melting-point metals and alloys, e.g., gallium (Ga), indium (In), tin (Sn), and Ga0.87Ag0.13 alloy. The valence states extracted from X-ray photoelectron spectroscopy (XPS) indicate that the ratios of oxidation to metal in our 2D films vary among metals. The temperature-dependent electronic measurements show that the transport behavior of 2D metal/metal oxide films conform with the 2D Mott’s variable range hopping (VRH) model. Our experiments provide a feasible and effective approach to obtain various 2D metals.
Collapse
|
14
|
Schneider L, Beck P, Neuhaus-Steinmetz J, Rózsa L, Posske T, Wiebe J, Wiesendanger R. Precursors of Majorana modes and their length-dependent energy oscillations probed at both ends of atomic Shiba chains. NATURE NANOTECHNOLOGY 2022; 17:384-389. [PMID: 35256768 PMCID: PMC9018407 DOI: 10.1038/s41565-022-01078-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 01/12/2022] [Indexed: 05/27/2023]
Abstract
Isolated Majorana modes (MMs) are highly non-local quantum states with non-Abelian exchange statistics, which localize at the two ends of finite-size 1D topological superconductors of sufficient length. Experimental evidence for MMs is so far based on the detection of several key signatures: for example, a conductance peak pinned to the Fermi energy or an oscillatory peak splitting in short 1D systems when the MMs overlap. However, most of these key signatures were probed only on one of the ends of the 1D system, and firm evidence for an MM requires the simultaneous detection of all the key signatures on both ends. Here we construct short atomic spin chains on a superconductor-also known as Shiba chains-up to a chain length of 45 atoms using tip-assisted atom manipulation in scanning tunnelling microscopy experiments. We observe zero-energy conductance peaks localized at both ends of the chain that simultaneously split off from the Fermi energy in an oscillatory fashion after altering the chain length. By fitting the parameters of a low-energy model to the data, we find that the peaks are consistent with precursors of MMs that evolve into isolated MMs protected by an estimated topological gap of 50 μeV in chains of at least 35 nm length, corresponding to 70 atoms.
Collapse
Affiliation(s)
- Lucas Schneider
- Department of Physics, Universität Hamburg, Hamburg, Germany
| | - Philip Beck
- Department of Physics, Universität Hamburg, Hamburg, Germany
| | | | - Levente Rózsa
- Department of Physics, University of Konstanz, Konstanz, Germany
| | - Thore Posske
- I. Institute for Theoretical Physics, Universität Hamburg, Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee, Hamburg, Germany
| | - Jens Wiebe
- Department of Physics, Universität Hamburg, Hamburg, Germany.
| | | |
Collapse
|
15
|
Ye C, Liu M. A computational study on the potential application of carbon nitride nanosheets in Na-ion batteries. J Mol Model 2022; 28:40. [DOI: 10.1007/s00894-021-05024-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 12/29/2021] [Indexed: 12/07/2022]
|
16
|
Ma MH, Batsaikhan E, Chen HN, Chen TY, Lee CH, Li WH, Wu CM, Wang CW. Non-conventional superconductivity in magnetic In and Sn nanoparticles. Sci Rep 2022; 12:775. [PMID: 35031677 PMCID: PMC8760274 DOI: 10.1038/s41598-022-04889-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/21/2021] [Indexed: 11/23/2022] Open
Abstract
We report on experimental evidence of non-conversional pairing in In and Sn nanoparticle assemblies. Spontaneous magnetizations are observed, through extremely weak-field magnetization and neutron-diffraction measurements, to develop when the nanoparticles enter the superconducting state. The superconducting transition temperature TC shifts to a noticeably higher temperature when an external magnetic field or magnetic Ni nanoparticles are introduced into the vicinity of the superconducting In or Sn nanoparticles. There is a critical magnetic field and a critical Ni composition that must be reached before the magnetic environment will suppress the superconductivity. The observations may be understood when assuming development of spin-parallel superconducting pairs on the surfaces and spin-antiparallel superconducting pairs in the core of the nanoparticles.
Collapse
Affiliation(s)
- Ma-Hsuan Ma
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | | | - Huang-Nan Chen
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | - Ting-Yang Chen
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | - Chi-Hung Lee
- Department of Physics, National Central University, Zhongli, 32001, Taiwan
| | - Wen-Hsien Li
- Department of Physics, National Central University, Zhongli, 32001, Taiwan.
| | - Chun-Ming Wu
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| | - Chin-Wei Wang
- National Synchrotron Radiation Research Center, Hsinchu, 30076, Taiwan
| |
Collapse
|
17
|
Borisova SD, Eremeev S, Rusina GG, Chulkov E. Surface Dynamics on submonolayer Pb/Cu(001) surfaces. Phys Chem Chem Phys 2022; 24:5164-5170. [DOI: 10.1039/d1cp05705g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The interplay of atomic structure and phonon spectra in variety of two dimensional phases forming at submonolayer Pb adsoption on the Cu(001) surface has been investigated using embedded atom method...
Collapse
|
18
|
Jin M, Yu P, Fan C, Li Q, Kong P, Shen Z, Qin X, Chi Z, Jin C, Liu G, Zhong G, Xu G, Liu Z, Zhu J. Discovery of Dome-Shaped Superconducting Phase and Anisotropic Transport in a van der Waals Layered Candidate NbIrTe 4 under Pressure. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:e2103250. [PMID: 34723437 PMCID: PMC8693038 DOI: 10.1002/advs.202103250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/26/2021] [Indexed: 06/13/2023]
Abstract
The unique electronic structure and crystal structure driven by external pressure in transition metal tellurides (TMTs) can host unconventional quantum states. Here, the discovery of pressure-induced phase transition at ≈2 GPa, and dome-shaped superconducting phase emerged in van der Waals layered NbIrTe4 is reported. The highest critical temperature (Tc ) is ≈5.8 K at pressure of ≈16 GPa, where the interlayered Te-Te covalent bonds form simultaneously derived from the synchrotron diffraction data, indicating the hosting structure of superconducting evolved from low-pressure two-dimensional (2D) phase to three-dimensional (3D) structure with pressure higher than 30 GPa. Strikingly, the authors have found an anisotropic transport in the vicinity of the superconducting state, suggesting the emergence of a "stripe"-like phase. The dome-shaped superconducting phase and anisotropic transport are possibly due to the spatial modulation of interlayer Josephson coupling .
Collapse
Affiliation(s)
- Meiling Jin
- Department of Physics and Shenzhen Engineering Research Center for Frontier Materials Synthesis at High PressuresSouthern University of Science and Technology (SUSTech)Shenzhen518055China
- Center for High Pressure Science and Technology Advanced Research (HPSTAR)Beijing100094China
| | - Peng Yu
- State Key Laboratory of Optoelectronic Materials and TechnologiesSchool of Materials Science and EngineeringSun Yat‐sen UniversityGuangzhou510275China
| | - Changzeng Fan
- State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao066004China
| | - Qiang Li
- Department of PhysicsShanghai Normal UniversityShanghai200234China
| | - Panlong Kong
- Center for High Pressure Science and Technology Advanced Research (HPSTAR)Beijing100094China
| | - Zhiwei Shen
- State Key Laboratory of Metastable Materials Science and TechnologyYanshan UniversityQinhuangdao066004China
| | - Xiaomei Qin
- Department of PhysicsShanghai Normal UniversityShanghai200234China
| | - Zhenhua Chi
- Institute of High Pressure PhysicsSchool of Physical Science and TechnologyNingbo UniversityNingbo315211China
| | - Changqing Jin
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesSchool of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
| | - Guangtong Liu
- Beijing National Laboratory for Condensed Matter PhysicsInstitute of PhysicsChinese Academy of SciencesSchool of Physical SciencesUniversity of Chinese Academy of SciencesBeijing100190China
| | - Guyue Zhong
- Wuhan National High Magnetic Field Center and School of PhysicsHuazhong University of Science and TechnologyWuhan430074China
| | - Gang Xu
- Wuhan National High Magnetic Field Center and School of PhysicsHuazhong University of Science and TechnologyWuhan430074China
| | - Zheng Liu
- School of Materials Science and EngineeringNanyang Technological University50 Nanyang AvenueSingapore639798Singapore
- School of Electrical and Electronic EngineeringNanyang Technological UniversitySingapore639798Singapore
| | - Jinlong Zhu
- Department of Physics and Shenzhen Engineering Research Center for Frontier Materials Synthesis at High PressuresSouthern University of Science and Technology (SUSTech)Shenzhen518055China
| |
Collapse
|
19
|
Sun W, Yang K, Wang Z, Niu M, Luo T, Su Z, Li R, Fu Q. Ultrahigh Molecular Weight Polyethylene Lamellar-Thin Framework on Square Meter Scale. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 34:e2107941. [PMID: 34794204 DOI: 10.1002/adma.202107941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/08/2021] [Indexed: 02/05/2023]
Abstract
A new member of low-dimensional structures with a high aspect ratio (LDHA) is introduced. For the first time, commodity polymer is processed into LDHA, which has long been stagnated by the lack of suitable processing techniques. The key to solve the current bottleneck is to overcome the trade-off between kinetic processability and thermodynamic stability. These two factors are both highly determined by intermolecular interaction level (IIL). Thus with a wide tuning range of IIL, ultrahigh molecular weight polyethylene (UHMWPE) is selected and investigated to break through the trade-off. Polymeric LDHA preparation needs both thinning and stiffening. By focusing on one then the other sequentially, they are realized simultaneously. Thus the over sixty-year-old material is finally thinned down by seven orders of magnitude into a 65.5 nm thick and 0.64 m2 large lamellar-thin framework (LTF). LTF exhibits a series of exceptional properties such as over-95% transparency, and seven times higher specific strength referred to steel. For the first time, cryogenic electron microscopy (Cryo-EM) is utilized to observe commodity polymers directly. This new LDHA material is promising to expand the scale boundaries of both fundamental research and practical applications, not only for UHMWPE, but also for more commodity polymers to come.
Collapse
Affiliation(s)
- Weilong Sun
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Kailin Yang
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Zirui Wang
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Mingze Niu
- State Key Laboratory of Biotherapy and Cancer Center Department of Geriatrics and National Clinical Research Center for Geriatrics West China Hospital Sichuan University Chengdu Sichuan 610041 P. R. China
| | - Tao Luo
- School of Chemical Engineering Sichuan University Chengdu 610065 P. R. China
| | - Zhaoming Su
- State Key Laboratory of Biotherapy and Cancer Center Department of Geriatrics and National Clinical Research Center for Geriatrics West China Hospital Sichuan University Chengdu Sichuan 610041 P. R. China
| | - Runlai Li
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| | - Qiang Fu
- College of Polymer Science & Engineering State Key Laboratory of Polymer Materials Engineering Sichuan University Chengdu 610065 P. R. China
| |
Collapse
|
20
|
Liu C, Zhao C, Zhong S, Chen C, Zhang Z, Jia Y, Wang J. Equally Spaced Quantum States in van der Waals Epitaxy-Grown Nanoislands. NANO LETTERS 2021; 21:9285-9292. [PMID: 34677982 DOI: 10.1021/acs.nanolett.1c03423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Pursuing the confinement of linearly dispersive relativistic Fermions is of interest in both fundamental physics and potential applications. Here, we report strong STM evidence for the equally spaced, strikingly sharp, and densely distributed quantum well states (QWSs) near Fermi energy in Pb(111) nanoislands, van der Waals epitaxially grown on graphitized 6H-SiC(0001). The observations can be explained as the quantized energies of confined linearly dispersive [111] electrons, which essentially "simulate" the out-of-plane relativistic quasiparticles. The equally spaced QWSs with an origin of confined relativistic electrons are supported by phenomenological simulations and Fabry-Pérot fittings based on the relativistic Fermions. First-principles calculations further reveal that the spin-orbit coupling strengthens the relativistic nature of electrons near Fermi energy. Our finding uncovers the unique equally spaced quantum states in electronic systems beyond Landau levels and may inspire future studies on confined relativistic quasiparticles in flourishing topological materials and applications in structurally simpler quantum cascade laser.
Collapse
Affiliation(s)
- Chaofei Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Chunxiang Zhao
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Shan Zhong
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Cheng Chen
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Zhenyu Zhang
- International Center for Quantum Design of Functional Materials (ICQD), Hefei National Laboratory for Physical Sciences at Microscale, and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei 230026, China
| | - Yu Jia
- International Laboratory for Quantum Functional Materials of Henan, and School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, China
| | - Jian Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| |
Collapse
|
21
|
Lu S, Nam H, Xiao P, Liu M, Guo Y, Bai Y, Cheng Z, Deng J, Li Y, Zhou H, Henkelman G, Fiete GA, Gao HJ, MacDonald AH, Zhang C, Shih CK. PTCDA Molecular Monolayer on Pb Thin Films: An Unusual π-Electron Kondo System and Its Interplay with a Quantum-Confined Superconductor. PHYSICAL REVIEW LETTERS 2021; 127:186805. [PMID: 34767397 DOI: 10.1103/physrevlett.127.186805] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
The hybridization of magnetism and superconductivity has been an intriguing playground for correlated electron systems, hosting various novel physical phenomena. Usually, localized d or f electrons are central to magnetism. In this study, by placing a PTCDA (3,4,9,10-perylene tetracarboxylic dianhydride) molecular monolayer on ultrathin Pb films, we built a hybrid magnetism/superconductivity (M/SC) system consisting of only sp electronic levels. The magnetic moments reside in the unpaired molecular orbital originating from interfacial charge transfers. We reported distinctive tunneling spectroscopic features of such a Kondo screened π electron impurity lattice on a superconductor in the regime of T_{K}≫Δ, suggesting the formation of a two-dimensional bound states band. Moreover, moiré superlattices with tunable twist angle and the quantum confinement in the ultrathin Pb films provide easy and flexible implementations to tune the interplay between the Kondo physics and the superconductivity, which are rarely present in M/SC hybrid systems.
Collapse
Affiliation(s)
- Shuangzan Lu
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Hyoungdo Nam
- Department of Physics, the University of Texas at Austin, Austin, Texas 78712, USA
| | - Penghao Xiao
- Department of Chemistry, the University of Texas at Austin, Austin, Texas 78712, USA
- Department of Physics & Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H4J5, Canada
| | - Mengke Liu
- Department of Physics, the University of Texas at Austin, Austin, Texas 78712, USA
| | - Yanping Guo
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Yusong Bai
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Zhengbo Cheng
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Jinghao Deng
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Yanxing Li
- Department of Physics, the University of Texas at Austin, Austin, Texas 78712, USA
| | - Haitao Zhou
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Graeme Henkelman
- Department of Chemistry, the University of Texas at Austin, Austin, Texas 78712, USA
| | - Gregory A Fiete
- Department of Physics, Northeastern University, Boston, Massachusetts 02115, USA
- Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Hong-Jun Gao
- Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Allan H MacDonald
- Department of Physics, the University of Texas at Austin, Austin, Texas 78712, USA
| | - Chendong Zhang
- School of Physics and Technology, Wuhan University, Wuhan 430072, China
| | - Chih-Kang Shih
- Department of Physics, the University of Texas at Austin, Austin, Texas 78712, USA
| |
Collapse
|
22
|
Li H, Wang H, Gao W, Chen Z, Han Y, Zhu X, Tian M. Thickness Dependence of Superconductivity in Layered Topological Superconductor β-PdBi 2. NANOMATERIALS (BASEL, SWITZERLAND) 2021; 11:2826. [PMID: 34835590 PMCID: PMC8618462 DOI: 10.3390/nano11112826] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/13/2021] [Accepted: 10/20/2021] [Indexed: 11/16/2022]
Abstract
We report a systematic study on the thickness-dependent superconductivity and transport properties in exfoliated layered topological superconductor β-PdBi2. The superconducting transition temperature Tc is found to decrease with the decreasing thickness. Below a critical thickness of 45 nm, the superconductivity is suppressed, but followed by an abrupt resistance jump near Tc, which is in opposite to the behavior in a superconductor. We attribute suppressed Tc to the enhanced disorder as the thickness decreases. The possible physical mechanisms were discussed for the origination of sharply increased resistance in thinner β-PdBi2 samples.
Collapse
Affiliation(s)
- Huijie Li
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China; (H.L.); (H.W.)
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, China; (Z.C.); (Y.H.); (X.Z.); (M.T.)
| | - Huanhuan Wang
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China; (H.L.); (H.W.)
| | - Wenshuai Gao
- Information Materials and Intelligent Sensing Laboratory of Anhui Province, Institutes of Physical Science and Information Technology, Anhui University, Hefei 230601, China; (H.L.); (H.W.)
| | - Zheng Chen
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, China; (Z.C.); (Y.H.); (X.Z.); (M.T.)
- Department of Physics, University of Science and Technology of China, Hefei 230031, China
| | - Yuyan Han
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, China; (Z.C.); (Y.H.); (X.Z.); (M.T.)
| | - Xiangde Zhu
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, China; (Z.C.); (Y.H.); (X.Z.); (M.T.)
| | - Mingliang Tian
- Anhui Key Laboratory of Condensed Matter Physics at Extreme Conditions, High Magnetic Field Laboratory, HFIPS, Anhui, Chinese Academy of Sciences, Hefei 230031, China; (Z.C.); (Y.H.); (X.Z.); (M.T.)
- School of Physics and Optoelectronic Engineering, Anhui University, Hefei 230601, China
| |
Collapse
|
23
|
Dai Z, Gao Z, Pershoguba SS, Tiwale N, Subramanian A, Zhang Q, Eads C, Tenney SA, Osgood RM, Nam CY, Zang J, Johnson ATC, Sadowski JT. Quantum-Well Bound States in Graphene Heterostructure Interfaces. PHYSICAL REVIEW LETTERS 2021; 127:086805. [PMID: 34477425 DOI: 10.1103/physrevlett.127.086805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/24/2021] [Indexed: 06/13/2023]
Abstract
We present experimental evidence of electronic and optical interlayer resonances in graphene van der Waals heterostructure interfaces. Using the spectroscopic mode of a low-energy electron microscope (LEEM), we characterized these interlayer resonant states up to 10 eV above the vacuum level. Compared with nontwisted, AB-stacked bilayer graphene (AB BLG), an ≈0.2 Å increase was found in the interlayer spacing of 30° twisted bilayer graphene (30°-tBLG). In addition, we used Raman spectroscopy to probe the inelastic light-matter interactions. A unique type of Fano resonance was found around the D and G modes of the graphene lattice vibrations. This anomalous, robust Fano resonance is a direct result of quantum confinement and the interplay between discrete phonon states and the excitonic continuum.
Collapse
Affiliation(s)
- Zhongwei Dai
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Zhaoli Gao
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
- Department of Biomedical Engineering, The Chinese University of Hong Kong, Hong Kong, China
| | - Sergey S Pershoguba
- Department of Physics and Astronomy and Materials Science Program, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - Nikhil Tiwale
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Ashwanth Subramanian
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
| | - Qicheng Zhang
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Calley Eads
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Samuel A Tenney
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| | - Richard M Osgood
- Department of Electrical Engineering, Columbia University, New York, New York 10027, USA
| | - Chang-Yong Nam
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
- Department of Materials Science and Chemical Engineering, Stony Brook University, Stony Brook, New York 11794, USA
| | - Jiadong Zang
- Department of Physics and Astronomy and Materials Science Program, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - A T Charlie Johnson
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Jerzy T Sadowski
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, New York 11973, USA
| |
Collapse
|
24
|
Fabrication of Superconducting Nanowires Using the Template Method. NANOMATERIALS 2021; 11:nano11081970. [PMID: 34443801 PMCID: PMC8398988 DOI: 10.3390/nano11081970] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/25/2021] [Accepted: 07/28/2021] [Indexed: 01/26/2023]
Abstract
The fabrication and characterization of superconducting nanowires fabricated by the anodic aluminium oxide (AAO) template technique has been reviewed. This templating method was applied to conventional metallic superconductors, as well as to several high-temperature superconductors (HTSc). For filling the templates with superconducting material, several different techniques have been applied in the literature, including electrodeposition, sol-gel techniques, sputtering, and melting. Here, we discuss the various superconducting materials employed and the results obtained. The arising problems in the fabrication process and the difficulties concerning the separation of the nanowires from the templates are pointed out in detail. Furthermore, we compare HTSc nanowires prepared by AAO templating and electrospinning with each other, and give an outlook to further research directions.
Collapse
|
25
|
Zhao X, Qiao J, Chan SM, Li J, Dan J, Ning S, Zhou W, Quek SY, Pennycook SJ, Loh KP. Unveiling Atomic-Scale Moiré Features and Atomic Reconstructions in High-Angle Commensurately Twisted Transition Metal Dichalcogenide Homobilayers. NANO LETTERS 2021; 21:3262-3270. [PMID: 33749268 DOI: 10.1021/acs.nanolett.1c00563] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Twisting the angle between van der Waals stacked 2D layers has recently sparked great interest as a new strategy to tune the physical properties of the materials. The twist angle and associated strain profiles govern the electrical and optical properties of the twisted 2D materials, but their detailed atomic structures remain elusive. Herein, using combined atomic-resolution electron microscopy and density functional theory (DFT) calculations, we identified five unique types of moiré features in commensurately twisted 7a×7a transition metal dichalcogenide (TMD) bilayers. These stacking variants are distinguishable only when the moiré wavelength is short. Periodic lattice strain is observed in various commensurately twisted TMD bilayers. Assisted by Zernike polynomial as a hierarchical active-learning framework, a hexagon-shaped strain soliton network has been atomically unveiled in nearly commensurate twisted TMD bilayers. Unlike stacking-polytype-dependent properties in untwisted structures, the stacking variants have the same electronic structures that suggest twisted bilayer systems are invariant against interlayer gliding.
Collapse
Affiliation(s)
- Xiaoxu Zhao
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore
- Department of Chemistry, National University of Singapore, 3 Science Drive 3 117543, Singapore
| | - Jingsi Qiao
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Si Min Chan
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Jing Li
- Department of Chemistry, National University of Singapore, 3 Science Drive 3 117543, Singapore
| | - Jiadong Dan
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore
| | - Shoucong Ning
- Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575, Singapore
| | - Wu Zhou
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Su Ying Quek
- Department of Physics, National University of Singapore, 2 Science Drive 3, 117542, Singapore
| | - Stephen John Pennycook
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kian Ping Loh
- Department of Chemistry, National University of Singapore, 3 Science Drive 3 117543, Singapore
| |
Collapse
|
26
|
Li J, Chen W, Liu J, Sun W, Li Z, Li Y. Effects of the nanowire length on large second-order nonlinear optical responses: a theoretical investigation of the thinnest doped beryllium nanowires with IR and UV working wavebands. Dalton Trans 2021; 50:4613-4622. [PMID: 33710193 DOI: 10.1039/d1dt00013f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The thinnest beryllium nanowires with high strength and uniformity are theoretically constructed of connected Be6 octahedron units. Based on this, Ca- and Mg-doped beryllium nanowires are successfully constructed and researched. They are unusual all-metal charge transfer salts Ca2+(Be6)n4-Mg2+ (n = 1-7), and they surprisingly display considerable second-order nonlinear optical (NLO) responses (β0e = 1.05 × 104-1.12 × 105 au). This is because the effect of doping Ca and Mg atoms brings great increase in β0e. In addition, more notably, the effect of the nanowire length on β0e revealed that the β0e value gradually and rapidly increases with the increase in the number of Be6 octahedron units (n). Thus, these doped beryllium nanowires are a new class of NLO nanowires. Fortunately, these NLO nanowires possess working wavebands in the infrared (IR, >2800 nm) and ultraviolet (UV, <200 nm) regions. Then, these doped beryllium NLO nanowires could also be used as new hot IR and UV NLO materials. Considering the dispersion effect, the frequency-dependent value of the electro-optical Pockels effect (EOPE) βe(-ω; ω, 0) at ω = 0.005 au is slightly larger than the corresponding value of β0e. Significantly, the effect of the nanowire length on βe(-ω; ω, 0) is also displayed. Obviously, a new design strategy of enhancing NLO responses by increasing n was obtained. Noticeably, the nanowires display Janus electronic properties of both stronger electron-donating and electron-withdrawing behaviors. This work predicts that novel metal nanowires may be applied in new hot IR and UV NLO materials as well as molecular electronic devices.
Collapse
Affiliation(s)
- Jing Li
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, College of Chemistry, Jilin University, Changchun, 130023, China.
| | | | | | | | | | | |
Collapse
|
27
|
Poojitha B, Reddy BH, Joshi A, Kumar A, Ali A, Singh RS, Saha S. Electron-phonon coupling in APd 3O 4: A = Ca, Sr, and Sr 0.85Li 0.15. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:105601. [PMID: 33260164 DOI: 10.1088/1361-648x/abcf60] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Here we have investigated the role of electron phonon coupling on the Raman spectrum of narrow bandgap semiconductors APd3O4 (A = Ca, Sr) and hole-doped system Sr0.85Li0.15Pd3O4. Four Raman active phonons are observed at room temperature for all three compounds as predicted by factor group analysis. The lowest energy phonon (∼190/202 cm-1) associated with Pd vibrations is observed to exhibit an asymmetric Fano-like lineshape in all the three compounds, indicating the presence of an interaction between the phonon and the electronic continuum. The origin of the electronic continuum states and electron-phonon coupling are discussed based on our laser power- and temperature-dependent Raman results. We have observed an enhanced strength of electron-phonon coupling in Sr0.85Li0.15Pd3O4 at low temperatures which can be attributed to the metallicity in this doped compound.
Collapse
Affiliation(s)
- Bommareddy Poojitha
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - B H Reddy
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - Aprajita Joshi
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - Ankit Kumar
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - Asif Ali
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - R S Singh
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| | - Surajit Saha
- Department of Physics, Indian Institute of Science Education and Research, Bhopal 462066, India
| |
Collapse
|
28
|
Fang Y, Wang D, Li P, Su H, Le T, Wu Y, Yang GW, Zhang HL, Xiao ZG, Sun YQ, Hong SY, Xie YW, Wang HH, Cao C, Lu X, Yuan HQ, Liu Y. Growth, electronic structure and superconductivity of ultrathin epitaxial CoSi 2films. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:155501. [PMID: 33498026 DOI: 10.1088/1361-648x/abdff6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Accepted: 01/26/2021] [Indexed: 06/12/2023]
Abstract
We report growth, electronic structure and superconductivity of ultrathin epitaxial CoSi2films on Si (111). At low coverages, preferred islands with 2, 5 and 6 monolayers height develop, which agrees well with the surface energy calculation. We observe clear quantum well states as a result of electronic confinement and their dispersion agrees well with density functional theory calculations, indicating weak correlation effect despite strong contributions from Co 3delectrons.Ex situtransport measurements show that superconductivity persists down to at least 10 monolayers, with reducedTcbut largely enhanced upper critical field. Our study opens up the opportunity to study the interplay between quantum confinement, interfacial symmetry breaking and superconductivity in an epitaxial silicide film, which is technologically relevant in microelectronics.
Collapse
Affiliation(s)
- Yuan Fang
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Ding Wang
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Peng Li
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Hang Su
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Tian Le
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Yi Wu
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Guo-Wei Yang
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Hua-Li Zhang
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Zhi-Guang Xiao
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Yan-Qiu Sun
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Si-Yuan Hong
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Yan-Wu Xie
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
| | - Huan-Hua Wang
- Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, People's Republic of China
| | - Chao Cao
- Department of Physics, Hangzhou Normal University, Hangzhou, People's Republic of China
| | - Xin Lu
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, People's Republic of China
| | - Hui-Qiu Yuan
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, People's Republic of China
| | - Yang Liu
- Center for Correlated Matter, Zhejiang University, Hangzhou, People's Republic of China
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou, People's Republic of China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, People's Republic of China
| |
Collapse
|
29
|
Measuring the Electron–Phonon Interaction in Two-Dimensional Superconductors with He-Atom Scattering. CONDENSED MATTER 2020. [DOI: 10.3390/condmat5040079] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Helium-atom scattering (HAS) spectroscopy from conducting surfaces has been shown to provide direct information on the electron–phonon interaction, more specifically the mass-enhancement factor λ from the temperature dependence of the Debye–Waller exponent, and the mode-selected electron–phonon coupling constants λQν from the inelastic HAS intensities from individual surface phonons. The recent applications of the method to superconducting ultra-thin films, quasi-1D high-index surfaces, and layered transition-metal and topological pnictogen chalcogenides are briefly reviewed.
Collapse
|
30
|
Superconductivity in undoped BaFe 2As 2 by tetrahedral geometry design. Proc Natl Acad Sci U S A 2020; 117:21170-21174. [PMID: 32817559 DOI: 10.1073/pnas.2001123117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fe-based superconductors exhibit a diverse interplay between charge, orbital, and magnetic ordering. Variations in atomic geometry affect electron hopping between Fe atoms and the Fermi surface topology, influencing magnetic frustration and the pairing strength through changes of orbital overlap and occupancies. Here, we experimentally demonstrate a systematic approach to realize superconductivity without chemical doping in BaFe2As2, employing geometric design within an epitaxial heterostructure. We control both tetragonality and orthorhombicity in BaFe2As2 through superlattice engineering, which we experimentally find to induce superconductivity when the As-Fe-As bond angle approaches that in a regular tetrahedron. This approach to superlattice design could lead to insights into low-dimensional superconductivity in Fe-based superconductors.
Collapse
|
31
|
Beladi-Mousavi SM, Ying Y, Plutnar J, Pumera M. Bismuthene Metallurgy: Transformation of Bismuth Particles to Ultrahigh-Aspect-Ratio 2D Microsheets. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002037. [PMID: 32519439 DOI: 10.1002/smll.202002037] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 05/07/2020] [Indexed: 06/11/2023]
Abstract
Ultrathin bismuth exhibits promising performance for topological insulators due to its narrow band gap and intrinsic strong spin-orbit coupling, as well as for energy-related applications because of its electronic and mechanical properties. However, large-scale production of 2D sheets via liquid-phase exfoliation as an established large-scale method is restricted by the strong interaction between bismuth layers. Here, a sonication method is utilized to produce ultrahigh-aspect-ratio bismuthene microsheets. The studies on the mechanism excludes the exfoliation of the layered bulk bismuth and formation of the microsheets is attributed to the melting of spherical particles (r = 1.5 µm) at a high temperature-generated under the ultrasonic tip-followed by a recrystallization step producing uniformly-shaped ultrathin microsheets (A = 0.5-2 µm2 , t: ≈2 nm). Notably, although the preparation is performed in oxygenated aqueous solution, the sheets are not oxidized, and they are stable under ambient conditions for at least 1 month. The microsheets are used to construct a vapor sensor using electrochemical impedance spectroscopy as detection technique. The device is highly selective, and it shows long-term stability. Overall, this project exhibits a reproducible method for large-scale preparation of ultrathin bismuthene microsheets in a benign environment, demonstrating opportunities to realize devices based on bismuthene.
Collapse
Affiliation(s)
- Seyyed Mohsen Beladi-Mousavi
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
| | - Yulong Ying
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
| | - Jan Plutnar
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
| | - Martin Pumera
- Center for the Advanced Functional Nanorobots, Department of Inorganic Chemistry, University of Chemistry and Technology, Technická 5, Prague, Czech Republic
- Department of Medical Research, China Medical University Hospital, China Medical University, No. 91 Hsueh-Shih Road, Taichung, Taiwan
- Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Korea
- Future Energy and Innovation Laboratory, Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, Brno, CZ-616 00, Czech Republic
| |
Collapse
|
32
|
The influence of phonon softening on the superconducting critical temperature of Sn nanostructures. Sci Rep 2020; 10:5729. [PMID: 32235906 PMCID: PMC7109077 DOI: 10.1038/s41598-020-62617-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 03/12/2020] [Indexed: 11/09/2022] Open
Abstract
The increase in superconducting transition temperature (TC) of Sn nanostructures in comparison to bulk, was studied. Changes in the phonon density of states (PDOS) of the weakly coupled superconductor Sn were analyzed and correlated with the increase in TC measured by magnetometry. The PDOS of all nanostructured samples shows a slightly increased number of low-energy phonon modes and a strong decrease in the number of high-energy phonon modes in comparison to the bulk Sn PDOS. The phonon densities of states, which were determined previously using nuclear resonant inelastic X-ray scattering, were used to calculate the superconducting transition temperature using the Allen-Dynes-McMillan (ADMM) formalism. Both the calculated as well as the experimentally determined values of TC show an increase compared to the bulk superconducting transition temperature. The good agreement between these values indicates that phonon softening has a major influence on the superconducting transition temperature of Sn nanostructures. The influence of electron confinement effects appears to be minor in these systems.
Collapse
|
33
|
Ito S, Arita M, Haruyama J, Feng B, Chen WC, Namatame H, Taniguchi M, Cheng CM, Bian G, Tang SJ, Chiang TC, Sugino O, Komori F, Matsuda I. Surface-state Coulomb repulsion accelerates a metal-insulator transition in topological semimetal nanofilms. SCIENCE ADVANCES 2020; 6:eaaz5015. [PMID: 32219169 PMCID: PMC7083614 DOI: 10.1126/sciadv.aaz5015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 12/30/2019] [Indexed: 06/10/2023]
Abstract
The emergence of quantization at the nanoscale, the quantum size effect (QSE), allows flexible control of matter and is a rich source of advanced functionalities. A QSE-induced transition into an insulating phase in semimetallic nanofilms was predicted for bismuth a half-century ago and has regained new interest with regard to its surface states exhibiting nontrivial electronic topology. Here, we reveal an unexpected mechanism of the transition by high-resolution angle-resolved photoelectron spectroscopy combined with theoretical calculations. Anomalous evolution and degeneracy of quantized energy levels indicate that increased Coulomb repulsion from the surface states deforms a quantum confinement potential with decreasing thickness. The potential deformation strongly modulates spatial distributions of quantized wave functions, which leads to acceleration of the transition beyond the original QSE picture. This discovery establishes a complete picture of the long-discussed transition and highlights a new class of size effects dominating nanoscale transport in systems with metallic surface states.
Collapse
Affiliation(s)
- S. Ito
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba, Japan
| | - M. Arita
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - J. Haruyama
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba, Japan
| | - B. Feng
- Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - W.-C. Chen
- Department of Physics and Astronomy, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
| | - H. Namatame
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - M. Taniguchi
- Hiroshima Synchrotron Radiation Center (HSRC), Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - C.-M. Cheng
- National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan, Republic of China
| | - G. Bian
- Department of Physics and Astronomy, University of Missouri, Columbia, MO, USA
| | - S.-J. Tang
- Department of Physics and Astronomy, National Tsing Hua University, Hsinchu, Taiwan, Republic of China
- National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan, Republic of China
| | - T.-C. Chiang
- Department of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - O. Sugino
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba, Japan
| | - F. Komori
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba, Japan
| | - I. Matsuda
- Institute for Solid State Physics (ISSP), The University of Tokyo, Kashiwa, Chiba, Japan
| |
Collapse
|
34
|
Analysis of Electronic Properties from Magnetotransport Measurements on Ba(Fe 1xNi x) 2As 2 Thin Films. MATERIALS 2020; 13:ma13030630. [PMID: 32023853 PMCID: PMC7040726 DOI: 10.3390/ma13030630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 01/26/2020] [Accepted: 01/28/2020] [Indexed: 11/17/2022]
Abstract
We performed a detailed structural, magnetotransport, and superconducting analysis of thin epitaxial Ba(Fe1-xNix)2As2 films with Ni doping of x = 0.05 and 0.08, as prepared by pulsed laser deposition. X-ray diffraction studies demonstrate the high crystalline perfection of the films, which have a similar quality to single crystals. Furthermore, magnetotransport measurements of the films were performed in magnetic fields up to 9 T. The results we used to estimate the density of electronic states at the Fermi level, the coefficient of electronic heat capacity, and other electronic parameters for this compound, in their dependence on the dopant concentration within the framework of the Ginzburg-Landau-Abrikosov-Gorkov theory. The comparison of the determined parameters with measurement data on comparable Ba(Fe1-xNix)2As2 single crystals shows good agreement, which confirms the high quality of the obtained films.
Collapse
|
35
|
Woo J, Shim H, Lee G. √7 × √3 surface with a double layer of In on Si(1 1 1) exhibiting both hexagonal and rectangular features. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:465001. [PMID: 31323654 DOI: 10.1088/1361-648x/ab33c9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Using a scanning tunneling microscope (STM), we demonstrate that the In-induced hexagonal (√7 × √3-hex) and rectangular (√7 × √3-rect) √7 × √3 phases on Si(111) are from the same surface with a double layer of In. The double-layer In thickness was derived from observations that a √7 × √3-hex island was formed on the √7 × √3-'striped' phase, which is believed to have a single layer of In atoms. Bias-dependent STM images were obtained from the same √7 × √3 domain and exhibited both √7 × √3-hex and √7 × √3-rect features, which led to the conclusion that both √7 × √3 STM features originate from the same structure. These findings are in stark contrast to the prevailing idea that there are two √7 × √3 surfaces with different structures and In coverage. We also observed a long-range Moiré-like superstructure in the √7 × √3 surface and attribute it to the mismatch of the lattices of the surface layer of In and the Si(1 1 1) substrate.
Collapse
Affiliation(s)
- Jeongseok Woo
- Department of Physics, Inha University, 100 Inha-ro, Michuhol-gu, Incheon 22212, Republic of Korea
| | | | | |
Collapse
|
36
|
Zhang J, Cai X, Xia W, Liang A, Huang J, Wang C, Yang L, Yuan H, Chen Y, Zhang S, Guo Y, Liu Z, Li G. Unveiling Electronic Correlation and the Ferromagnetic Superexchange Mechanism in the van der Waals Crystal CrSiTe_{3}. PHYSICAL REVIEW LETTERS 2019; 123:047203. [PMID: 31491273 DOI: 10.1103/physrevlett.123.047203] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 04/27/2019] [Indexed: 06/10/2023]
Abstract
The recent discovery of intrinsic ferromagnetic order in the atomically thin van der Waals crystal CrXTe_{3} (X=Si, Ge) stimulates intensive studies on the nature of low-dimensional magnetism because the presence of long-range magnetic order in two-dimensional systems with continuous symmetry is strictly prohibited by thermal fluctuations. By combining advanced many-body calculations with angle-resolved photoemission spectroscopy we investigate CrSiTe_{3} single crystals and unveil the pivotal role played by the strong electronic correlations at both high- and low-temperature regimes. Above the Curie temperature (T_{c}), Coulomb repulsion (U) drives the system into a charge transfer insulating phase. In contrast, below T_{c} the crystal field arranges the Cr-3d orbitals such that the ferromagnetic superexchange profits, giving rise to the bulk ferromagnetic ground state with which the electronic correlations compete. The excellent agreement between theory and experiment establishes CrSiTe_{3} as a prototype low-dimensional crystal with the cooperation and interplay of electronic correlation and ferromagnetism.
Collapse
Affiliation(s)
- Jiaxin Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Xiaochan Cai
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Wei Xia
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Aiji Liang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Junwei Huang
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Chengwei Wang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Lexian Yang
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
| | - Hongtao Yuan
- National Laboratory of Solid-State Microstructures, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
| | - Yulin Chen
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, People's Republic of China
- Department of Physics, University of Oxford, Oxford OX1 3PU, United Kingdom
| | - Shilei Zhang
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Yanfeng Guo
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Zhongkai Liu
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| | - Gang Li
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 200031, China
| |
Collapse
|
37
|
Liu C, Wang G, Wang J. Manipulating the particle-hole symmetry of quasiparticle bound states in geometric-size-varying Fe clusters on one-unit-cell FeSe/SrTiO 3(0 0 1). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:285002. [PMID: 30947147 DOI: 10.1088/1361-648x/ab1630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The particle-hole symmetry (PHS) of quasiparticle bound states, which is generally expected in theory, is present or absent experimentally in a seemingly irregular manner, with the physical origin little understood yet. Here, we report a study on the bound states induced by Fe clusters with different sizes on one-unit-cell (1-UC) FeSe/SrTiO3(0 0 1) by in situ scanning tunneling spectroscopy. Statistically, on the larger-scale cluster, a pair of bias-symmetric minipeaks are detected within the superconducting-gap energies. As increasing temperature, the minipeak states show negligible energy dispersion. The temperature-independent bias-symmetric minipeaks are identified as the quasiparticle bound states that preserve the PHS. However, on the smaller-scale cluster, the bound state appears as a single resonance instead. These results reveal a geometric-size-tuning effect of the PHS, which may help reconcile the contradiction between the superconductivity theory and the PHS-breaking experiments.
Collapse
Affiliation(s)
- Chaofei Liu
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | | | | |
Collapse
|
38
|
Cross-dimensional electron-phonon coupling in van der Waals heterostructures. Nat Commun 2019; 10:2419. [PMID: 31160599 PMCID: PMC6546732 DOI: 10.1038/s41467-019-10400-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/08/2019] [Indexed: 11/12/2022] Open
Abstract
The electron-phonon coupling (EPC) in a material is at the frontier of the fundamental research, underlying many quantum behaviors. van der Waals heterostructures (vdWHs) provide an ideal platform to reveal the intrinsic interaction between their electrons and phonons. In particular, the flexible van der Waals stacking of different atomic crystals leads to multiple opportunities to engineer the interlayer phonon modes for EPC. Here, in hBN/WS2 vdWH, we report the strong cross-dimensional coupling between the layer-breathing phonons well extended over tens to hundreds of layer thick vdWH and the electrons localized within the few-layer WS2 constituent. The strength of such cross-dimensional EPC can be well reproduced by a microscopic picture through the mediation by the interfacial coupling and also the interlayer bond polarizability model in vdWHs. The study on cross-dimensional EPC paves the way to manipulate the interaction between electrons and phonons in various vdWHs by interfacial engineering for possible interesting physical phenomena. The strength of electron-phonon coupling can be directly probed by Raman spectroscopy. Here, the authors use low-frequency Raman spectroscopy to unveil the existence of a strong cross-dimensional coupling between the bulk-like layer-breathing phonons in an hBN/WS2 heterostructure and the electrons localized within its few-layer WS2 constituent.
Collapse
|
39
|
Peng L, Qiao J, Xian JJ, Pan Y, Ji W, Zhang W, Fu YS. Unusual Electronic States and Superconducting Proximity Effect of Bi Films Modulated by a NbSe 2 Substrate. ACS NANO 2019; 13:1885-1892. [PMID: 30653300 DOI: 10.1021/acsnano.8b08051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Heterostructures of two-dimensional layered materials can be functionalized with exotic phenomena that are unpresented with each constituting component. The interface effect plays a key role in determining the electronic properties of the heterostructure, whose characterization requires a correlation with the morphology with atomic-scale precision. Here, we report an investigation on the electronic properties of few-layer Bi(110) films mediated by a NbSe2 substrate. By utilizing scanning tunneling microscopy and spectroscopy, we show a significant variation of the density of states at different Bi film thicknesses, resulting in an unusual superconducting proximity effect that deviates from the conventional monotonous decay behavior. Moreover, the electronic states of the Bi films are also prominently modulated by the Moiré pattern spatially. With first-principles calculations, we illuminate these findings as the results of covalent-like quasi-bonds formed at the Bi/NbSe2 interface, which profoundly alter the charge distributions in the Bi films. Our study indicates a viable way of modulating the electronic properties of ultrathin films by quasi-covalent interfacial couplings beyond conventional van der Waals interactions.
Collapse
Affiliation(s)
- Lang Peng
- School of Physics and Wuhan National High Magnetic Field Center , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Jingsi Qiao
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics , Renmin University of China , Beijing 100872 , China
| | - Jing-Jing Xian
- School of Physics and Wuhan National High Magnetic Field Center , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Yuhao Pan
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics , Renmin University of China , Beijing 100872 , China
| | - Wei Ji
- Beijing Key Laboratory of Optoelectronic Functional Materials & Micro-Nano Devices, Department of Physics , Renmin University of China , Beijing 100872 , China
| | - Wenhao Zhang
- School of Physics and Wuhan National High Magnetic Field Center , Huazhong University of Science and Technology , Wuhan 430074 , China
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center , Huazhong University of Science and Technology , Wuhan 430074 , China
| |
Collapse
|
40
|
Yan L, Bo T, Zhang W, Liu PF, Lu Z, Xiao YG, Tang MH, Wang BT. Novel structures of two-dimensional tungsten boride and their superconductivity. Phys Chem Chem Phys 2019; 21:15327-15338. [DOI: 10.1039/c9cp02727k] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We predict four new tungsten boride monolayers and demonstrate that two of them are phonon-mediated superconductors with superconducting transition temperatures of 7.8 and 1.5 K.
Collapse
Affiliation(s)
- Luo Yan
- Key Laboratory of Key Film Materials & Application for Equipments (Hunan Province)
- School of Material Sciences and Engineering
- Xiangtan University
- Xiangtan
- China
| | - Tao Bo
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Institute of Neutron Science (DINS)
| | - Wenxue Zhang
- Collaborative Innovation Center of Extreme Optics
- Shanxi University
- Taiyuan
- China
- State Key Laboratory of Quantum Optics and Quantum Optics Devices
| | - Peng-Fei Liu
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Institute of Neutron Science (DINS)
| | - Zhansheng Lu
- College of Physics and Materials Science
- Henan Normal University
- Xinxiang 453007
- China
| | - Yong-Guang Xiao
- Key Laboratory of Key Film Materials & Application for Equipments (Hunan Province)
- School of Material Sciences and Engineering
- Xiangtan University
- Xiangtan
- China
| | - Ming-Hua Tang
- Key Laboratory of Key Film Materials & Application for Equipments (Hunan Province)
- School of Material Sciences and Engineering
- Xiangtan University
- Xiangtan
- China
| | - Bao-Tian Wang
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Institute of Neutron Science (DINS)
| |
Collapse
|
41
|
Nam H, Chen H, Adams PW, Guan SY, Chuang TM, Chang CS, MacDonald AH, Shih CK. Geometric quenching of orbital pair breaking in a single crystalline superconducting nanomesh network. Nat Commun 2018; 9:5431. [PMID: 30575727 PMCID: PMC6303408 DOI: 10.1038/s41467-018-07778-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/12/2018] [Indexed: 11/09/2022] Open
Abstract
In a superconductor Cooper pairs condense into a single state and in so doing support dissipation free charge flow and perfect diamagnetism. In a magnetic field the minimum kinetic energy of the Cooper pairs increases, producing an orbital pair breaking effect. We show that it is possible to significantly quench the orbital pair breaking effect for both parallel and perpendicular magnetic fields in a thin film superconductor with lateral nanostructure on a length scale smaller than the magnetic length. By growing an ultra-thin (2 nm thick) single crystalline Pb nanowire network, we establish nm scale lateral structure without introducing weak links. Our network suppresses orbital pair breaking for both perpendicular and in-plane fields with a negligible reduction in zero-field resistive critical temperatures. Our study opens a frontier in nanoscale superconductivity by providing a strategy for maintaining pairing in strong field environments in all directions with important technological implications.
Collapse
Affiliation(s)
- Hyoungdo Nam
- Department of Physics, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Hua Chen
- Department of Physics, Colorado State University, Fort Collins, CO, 80523, USA
| | - Philip W Adams
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Syu-You Guan
- Institute of Physics, Academia Sinica, Nankang, 11529, Taipei, Taiwan
| | - Tien-Ming Chuang
- Institute of Physics, Academia Sinica, Nankang, 11529, Taipei, Taiwan
| | - Chia-Seng Chang
- Institute of Physics, Academia Sinica, Nankang, 11529, Taipei, Taiwan
| | - Allan H MacDonald
- Department of Physics, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Chih-Kang Shih
- Department of Physics, The University of Texas at Austin, Austin, TX, 78712, USA.
| |
Collapse
|
42
|
Zhang E, Zhi J, Zou YC, Ye Z, Ai L, Shi J, Huang C, Liu S, Lin Z, Zheng X, Kang N, Xu H, Wang W, He L, Zou J, Liu J, Mao Z, Xiu F. Signature of quantum Griffiths singularity state in a layered quasi-one-dimensional superconductor. Nat Commun 2018; 9:4656. [PMID: 30405120 PMCID: PMC6220168 DOI: 10.1038/s41467-018-07123-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 10/18/2018] [Indexed: 11/08/2022] Open
Abstract
Quantum Griffiths singularity was theoretically proposed to interpret the phenomenon of divergent dynamical exponent in quantum phase transitions. It has been discovered experimentally in three-dimensional (3D) magnetic metal systems and two-dimensional (2D) superconductors. But, whether this state exists in lower dimensional systems remains elusive. Here, we report the signature of quantum Griffiths singularity state in quasi-one-dimensional (1D) Ta2PdS5 nanowires. The superconducting critical field shows a strong anisotropic behavior and a violation of the Pauli limit in a parallel magnetic field configuration. Current-voltage measurements exhibit hysteresis loops and a series of multiple voltage steps in transition to the normal state, indicating a quasi-1D nature of the superconductivity. Surprisingly, the nanowire undergoes a superconductor-metal transition when the magnetic field increases. Upon approaching the zero-temperature quantum critical point, the system uncovers the signature of the quantum Griffiths singularity state arising from enhanced quenched disorders, where the dynamical critical exponent becomes diverging rather than being constant.
Collapse
Affiliation(s)
- Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Jinhua Zhi
- Bejing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, 100871, Beijing, China
| | - Yi-Chao Zou
- Materials Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zefang Ye
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Linfeng Ai
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Jiacheng Shi
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Ce Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Zehao Lin
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Xinyuan Zheng
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China
| | - Ning Kang
- Bejing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, 100871, Beijing, China
| | - Hongqi Xu
- Bejing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices and Department of Electronics, Peking University, 100871, Beijing, China
| | - Wei Wang
- School of Electronics Science and Engineering, Nanjing University, 210093, Nanjing, China
| | - Liang He
- School of Electronics Science and Engineering, Nanjing University, 210093, Nanjing, China
| | - Jin Zou
- Materials Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia
- Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jinyu Liu
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, 70118, USA
| | - Zhiqiang Mao
- Department of Physics and Engineering Physics, Tulane University, New Orleans, LA, 70118, USA
| | - Faxian Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, 200433, Shanghai, China.
- Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, 200433, Shanghai, China.
- Collaborative Innovation Center of Advanced Microstructures, Nanjing University, 210093, Nanjing, China.
| |
Collapse
|
43
|
Nagli M, Caspary Toroker M. Communication: Nickel hydroxide as an exceptional deviation from the quantum size effect. J Chem Phys 2018; 149:141103. [PMID: 30316282 DOI: 10.1063/1.5051202] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The quantum size effect is a well-known fundamental scientific phenomenon. Due to quantum confinement, downscaling a system to small sizes should increase the bandgap of a solid state material. However, in this work, we present an exception: monolayers of nickel hydroxide have smaller bandgaps than their bulk analogues, due to the surface states appearing at energies within the bandgap region. Our findings are obtained by several state-of-the-art first principles calculations.
Collapse
Affiliation(s)
- Michael Nagli
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| | - Maytal Caspary Toroker
- Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 3200003, Israel
| |
Collapse
|
44
|
Guo B, Wang SH, Wu ZX, Wang ZX, Wang DH, Huang H, Zhang F, Ge YQ, Zhang H. Sub-200 fs soliton mode-locked fiber laser based on bismuthene saturable absorber. OPTICS EXPRESS 2018; 26:22750-22760. [PMID: 30184930 DOI: 10.1364/oe.26.022750] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Few-layer bismuthene is an emerging two-dimensional material in the fields of physics, chemistry, and material science. However, its nonlinear optical property and the related photonics device have been seldom studied so far. Here, we demonstrate a sub-200 fs soliton mode-locked erbium-doped fiber laser (EDFL) using a microfiber-based bismuthene saturable absorber for the first time, to the best of our knowledge. The bismuthene nanosheets are synthesized by the sonochemical exfoliation method and transferred onto the taper region of a microfiber by the optical deposition method. Stable soliton pulses centered at 1561 nm with the shortest pulse duration of about 193 fs were obtained. Our findings unambiguously imply that apart from its fantastic electric and thermal properties, few-layer bismuthene may also possess attractive optoelectronic properties for nonlinear photonics, such as mode-lockers, Q-switchers, optical modulators and so on.
Collapse
|
45
|
Hao J, Zheng J, Ling F, Chen Y, Jing H, Zhou T, Fang L, Zhou M. Strain-engineered two-dimensional MoS 2 as anode material for performance enhancement of Li/Na-ion batteries. Sci Rep 2018; 8:2079. [PMID: 29391534 PMCID: PMC5794781 DOI: 10.1038/s41598-018-20334-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 01/16/2018] [Indexed: 11/09/2022] Open
Abstract
Recent years have witnessed a surge of research in two-dimensional (2D) nanostructures for development of new rechargeable Li/Na-ion battery systems. Herein, via first-principles calculations we demonstrate strain-engineered Li/Na adsorption and storage in 2D MoS2 as anode material, aiming to enhance the operating performance of Li/Na-ion batteries. Our results show that tensile strain greatly increases the adsorption of Li/Na atoms on MoS2, and a modest strain of 6% increases Li (Na) adsorption energy by over 70%, which originates from the strain-induced upshift of Mo d states towards Fermi level that interact strongly with Li/Na s states, in analogy with the d-band model in metal catalyst. Significant narrowing of the n-doped semiconducting gap of MoS2 suggests the improved electric conductivity that may benefit charge carrier transport. By mapping out the potential energy surfaces, we show shallow energy barriers of ion diffusion with ~0.2 eV for Li and 0.1 eV for Na. Furthermore, the strain-steered competition between chemical bonding and coulomb repulsion results in high Li/Na storage capability and relatively low average operating voltage. We believe that the fundamental principle underlying the use of strain to enhance performance of renewable ion battery is applicable to other stretchable low-dimensional nanomaterials.
Collapse
Affiliation(s)
- Jiongyue Hao
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China
| | - Junfeng Zheng
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China
| | - Faling Ling
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China
| | - Yankun Chen
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China
| | - Huirong Jing
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China
| | - Tingwei Zhou
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China
| | - Liang Fang
- Department of Applied Physics, College of Physics, Chongqing University, Chongqing, 401331, China
| | - Miao Zhou
- Key Laboratory of Optoelectronic Technology & Systems (Ministry of Education), College of Optoeletronic Engineering, Chongqing University, Chongqing, 400044, China.
| |
Collapse
|
46
|
Goncharuk VV, Skilskaya MD, Romanyukina IY, Marinin AI, Dolenko SA. Influence of the concentration of deuterium on structural changes of aqueous solutions. J WATER CHEM TECHNO+ 2018. [DOI: 10.3103/s1063455x17060054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
47
|
Liu PF, Wu Y, Bo T, Hou L, Xu J, Zhang HJ, Wang BT. Square transition-metal carbides MC6 (M = Mo, W) as stable two-dimensional Dirac cone materials. Phys Chem Chem Phys 2018; 20:732-737. [DOI: 10.1039/c7cp07466b] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We identify the existence of Dirac cones in 2D square transition-metal carbides MC6 (M = Mo, W) with an ultrahigh Fermi velocity comparable to that of graphene.
Collapse
Affiliation(s)
- Peng-Fei Liu
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| | - Yang Wu
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| | - Tao Bo
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| | - Ling Hou
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| | - Juping Xu
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| | - Hui-jie Zhang
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| | - Bao-Tian Wang
- Institute of High Energy Physics
- Chinese Academy of Sciences (CAS)
- Beijing 100049
- China
- Dongguan Neutron Science Center
| |
Collapse
|
48
|
Formation of Surface and Quantum-Well States in Ultra Thin Pt Films on the Au(111) Surface. MATERIALS 2017; 10:ma10121409. [PMID: 29232833 PMCID: PMC5744344 DOI: 10.3390/ma10121409] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 12/05/2017] [Accepted: 12/07/2017] [Indexed: 12/22/2022]
Abstract
The electronic structure of the Pt/Au(111) heterostructures with a number of Pt monolayers n ranging from one to three is studied in the density-functional-theory framework. The calculations demonstrate that the deposition of the Pt atomic thin films on gold substrate results in strong modifications of the electronic structure at the surface. In particular, the Au(111) s-p-type Shockley surface state becomes completely unoccupied at deposition of any number of Pt monolayers. The Pt adlayer generates numerous quantum-well states in various energy gaps of Au(111) with strong spatial confinement at the surface. As a result, strong enhancement in the local density of state at the surface Pt atomic layer in comparison with clean Pt surface is obtained. The excess in the density of states has maximal magnitude in the case of one monolayer Pt adlayer and gradually reduces with increasing number of Pt atomic layers. The spin-orbit coupling produces strong modification of the energy dispersion of the electronic states generated by the Pt adlayer and gives rise to certain quantum states with a characteristic Dirac-cone shape.
Collapse
|
49
|
Mika M, Wójcik P. Fulde-Ferrell state in superconducting core/shell nanowires: role of the orbital effect. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:475302. [PMID: 28980531 DOI: 10.1088/1361-648x/aa913e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The orbital effect on the Fulde-Ferrell (FF) phase is investigated in superconducting core/shell nanowires subjected to the axial magnetic field. Confinement in the radial direction results in quantization of the electron motion with energies determined by the radial j and orbital m quantum numbers. In the external magnetic field, the twofold degeneracy with respect to the orbital magnetic quantum number m is lifted which leads to the Fermi wave vector mismatch between the paired electrons, [Formula: see text]. This mismatch is transferred to the nonzero total momentum of the Cooper pairs, which results in a formation of the FF phase occurring sequentially with increasing magnetic field. By changing the nanowire radius R and the superconducting shell thickness d, we discuss the role of the orbital effect in the FF phase formation in both the nanowire-like ([Formula: see text]) and nanofilm-like ([Formula: see text]) regime. We have found that the irregular pattern of the FF phase which appears for the case of the nanowire-like regime, for the nanofilm-like geometry evolves towards the regular distribution in which the FF phase stability regions emerge periodically between the BCS states. The transition between these two different phase diagrams is explained as resulting from the orbital effect and the multigap character of superconductivity in the core/shell nanowires.
Collapse
Affiliation(s)
- Marek Mika
- AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. A. Mickiewicza 30, 30-059 Krakow, Poland
| | | |
Collapse
|
50
|
Paul JT, Singh AK, Dong Z, Zhuang H, Revard BC, Rijal B, Ashton M, Linscheid A, Blonsky M, Gluhovic D, Guo J, Hennig RG. Computational methods for 2D materials: discovery, property characterization, and application design. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:473001. [PMID: 29022886 DOI: 10.1088/1361-648x/aa9305] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The discovery of two-dimensional (2D) materials comes at a time when computational methods are mature and can predict novel 2D materials, characterize their properties, and guide the design of 2D materials for applications. This article reviews the recent progress in computational approaches for 2D materials research. We discuss the computational techniques and provide an overview of the ongoing research in the field. We begin with an overview of known 2D materials, common computational methods, and available cyber infrastructures. We then move onto the discovery of novel 2D materials, discussing the stability criteria for 2D materials, computational methods for structure prediction, and interactions of monolayers with electrochemical and gaseous environments. Next, we describe the computational characterization of the 2D materials' electronic, optical, magnetic, and superconducting properties and the response of the properties under applied mechanical strain and electrical fields. From there, we move on to discuss the structure and properties of defects in 2D materials, and describe methods for 2D materials device simulations. We conclude by providing an outlook on the needs and challenges for future developments in the field of computational research for 2D materials.
Collapse
Affiliation(s)
- J T Paul
- Department of Materials Science and Engineering, University of Florida, Gainesville, Fl 32611, United States of America
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|