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Borisova SD, Eremeev SV, Chulkov EV, Rusina GG. Lead overlayer dynamics on Ni(111). Phys Chem Chem Phys 2024; 26:16184-16190. [PMID: 38804157 DOI: 10.1039/d4cp01210k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Ultrathin lead films on metallic and semiconductor substrates are technologically demanded and actively studied by different experimental and theoretical methods. The formation of these films gives rise to new adsorbate-induced electron states and vibrational modes. The dynamical properties of atoms on surfaces depend sensitively on their bonding environment and thus provide valuable insight into the local geometry and chemical bonding at the boundary of a solid. In this paper, the vibrational properties of the , (3 × 3) and (4 × 4) overlayers formed by the adsorption of 1/3, 4/9, and 9/16 Pb ML, respectively, on the Ni(111) surface were studied for the first time. The surface relaxations, phonon modes and the local density of states were analyzed. We revealed the role of substrate dynamics in the stability of the Pb/Ni(111) system at submonolayer Pb adsorption.
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Affiliation(s)
- Svetlana D Borisova
- Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences, 634055 Tomsk, Russia.
| | - Sergey V Eremeev
- Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences, 634055 Tomsk, Russia.
| | - Evgueni V Chulkov
- Departamento de Polímeros y Materiales Avanzados, Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco (UPV-EHU), E-20080 San Sebastián, Spain
- Donostia International Physics Center (DIPC), E-20018 San Sebastián, Spain
| | - Galina G Rusina
- Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences, 634055 Tomsk, Russia.
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Wolf S, Di Sante D, Schwemmer T, Thomale R, Rachel S. Triplet Superconductivity from Nonlocal Coulomb Repulsion in an Atomic Sn Layer Deposited onto a Si(111) Substrate. PHYSICAL REVIEW LETTERS 2022; 128:167002. [PMID: 35522509 DOI: 10.1103/physrevlett.128.167002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Atomic layers deposited on semiconductor substrates introduce a platform for the realization of the extended electronic Hubbard model, where the consideration of electronic repulsion beyond the on-site term is paramount. Recently, the onset of superconductivity at 4.7 K has been reported in the hole-doped triangular lattice of tin atoms on a silicon substrate. Through renormalization group methods designed for weak and intermediate coupling, we investigate the nature of the superconducting instability in hole-doped Sn/Si(111). We find that the extended Hubbard nature of interactions is crucial to yield triplet pairing, which is f-wave (p-wave) for moderate (higher) hole doping. In light of persisting challenges to tailor triplet pairing in an electronic material, our finding promises to pave unprecedented ways for engineering unconventional triplet superconductivity.
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Affiliation(s)
- Sebastian Wolf
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
| | - Domenico Di Sante
- Department of Physics and Astronomy, University of Bologna, 40127 Bologna, Italy
- Center for Computational Quantum Physics, Flatiron Institute, New York, New York 10010, USA
| | - Tilman Schwemmer
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - Ronny Thomale
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland Campus Süd, Würzburg 97074, Germany
| | - Stephan Rachel
- School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia
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3
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Stolyarov VS, Pons S, Vlaic S, Remizov SV, Shapiro DS, Brun C, Bozhko SI, Cren T, Menshchikova TV, Chulkov EV, Pogosov WV, Lozovik YE, Roditchev D. Superconducting Long-Range Proximity Effect through the Atomically Flat Interface of a Bi 2Te 3 Topological Insulator. J Phys Chem Lett 2021; 12:9068-9075. [PMID: 34516738 DOI: 10.1021/acs.jpclett.1c02257] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
We report on structural and electronic properties of superconducting nanohybrids made of Pb grown in the ultrahigh vacuum on the atomically clean surface of single crystals of topological Bi2Te3. In situ scanning tunneling microscopy and spectroscopy demonstrated that the resulting network is composed of Pb-nanoislands dispersed on the surface and linked together by an amorphous atomic layer of Pb, which wets Bi2Te3. As a result, the superconducting state of the system is characterized by a thickness-dependent superconducting gap of Pb-islands and by a very unusual position-independent proximity gap between them. Furthermore, the data analysis and DFT calculations demonstrate that the Pb-wetting layer leads to significant modifications of both topological and trivial electronic states of Bi2Te3, which are responsible for the observed long-range proximity effect.
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Affiliation(s)
- Vasily S Stolyarov
- Laboratoire de Physique et d'Etudes des Matériaux, LPEM, UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne University, 75005 Paris, France
- TQPSS Lab, Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Moscow, Russia
- Dukhov Research Institute of Automatics (VNIIA), Moscow 127055, Russia
| | - Stephane Pons
- Laboratoire de Physique et d'Etudes des Matériaux, LPEM, UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne University, 75005 Paris, France
| | - Sergio Vlaic
- Laboratoire de Physique et d'Etudes des Matériaux, LPEM, UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne University, 75005 Paris, France
| | - Sergey V Remizov
- Dukhov Research Institute of Automatics (VNIIA), Moscow 127055, Russia
| | - Dmitriy S Shapiro
- Dukhov Research Institute of Automatics (VNIIA), Moscow 127055, Russia
| | - Christophe Brun
- Institut des Nanosciences de Paris, UMR-7588, CNRS, Sorbonne University, F-75005 Paris, France
| | - Sergey I Bozhko
- Institute of Solid State Physics RAS, 142432 Chernogolovka, Russia
| | - Tristan Cren
- Institut des Nanosciences de Paris, UMR-7588, CNRS, Sorbonne University, F-75005 Paris, France
| | | | - Evgueni V Chulkov
- Departamento de Polí meros y Materiales Avanzados: Física, Química y Tecnología, Facultad de Ciencias Químicas, Universidad del País Vasco UPV/EHU, Apartado 1072, 20080 San Sebastian/Donostia, Spain
- HSE University, 109028 Moscow, Russia
- Donostia International Physics Center (DIPC), San Sebastián/Donostia 20018, Basque Country, Spain
| | - Walter V Pogosov
- Dukhov Research Institute of Automatics (VNIIA), Moscow 127055, Russia
- Institute for Theoretical and Applied Electrodynamics, Russian Academy of Sciences, 125412 Moscow, Russia
- HSE University, 109028 Moscow, Russia
| | - Yuriy E Lozovik
- Dukhov Research Institute of Automatics (VNIIA), Moscow 127055, Russia
- Institute of Spectroscopy RAS 108840 Troitsk, Moscow, Russia
- HSE University, 109028 Moscow, Russia
| | - Dimitri Roditchev
- Laboratoire de Physique et d'Etudes des Matériaux, LPEM, UMR-8213, ESPCI Paris, PSL Research University, CNRS, Sorbonne University, 75005 Paris, France
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Kapcia KJ. Charge-Order on the Triangular Lattice: A Mean-Field Study for the Lattice S = 1/2 Fermionic Gas. NANOMATERIALS 2021; 11:nano11051181. [PMID: 33946175 PMCID: PMC8145665 DOI: 10.3390/nano11051181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/27/2021] [Accepted: 04/29/2021] [Indexed: 11/29/2022]
Abstract
The adsorbed atoms exhibit tendency to occupy a triangular lattice formed by periodic potential of the underlying crystal surface. Such a lattice is formed by, e.g., a single layer of graphane or the graphite surfaces as well as (111) surface of face-cubic center crystals. In the present work, an extension of the lattice gas model to S=1/2 fermionic particles on the two-dimensional triangular (hexagonal) lattice is analyzed. In such a model, each lattice site can be occupied not by only one particle, but by two particles, which interact with each other by onsite U and intersite W1 and W2 (nearest and next-nearest-neighbor, respectively) density-density interaction. The investigated hamiltonian has a form of the extended Hubbard model in the atomic limit (i.e., the zero-bandwidth limit). In the analysis of the phase diagrams and thermodynamic properties of this model with repulsive W1>0, the variational approach is used, which treats the onsite interaction term exactly and the intersite interactions within the mean-field approximation. The ground state (T=0) diagram for W2≤0 as well as finite temperature (T>0) phase diagrams for W2=0 are presented. Two different types of charge order within 3×3 unit cell can occur. At T=0, for W2=0 phase separated states are degenerated with homogeneous phases (but T>0 removes this degeneration), whereas attractive W2<0 stabilizes phase separation at incommensurate fillings. For U/W1<0 and U/W1>1/2 only the phase with two different concentrations occurs (together with two different phase separated states occurring), whereas for small repulsive 0<U/W1<1/2 the other ordered phase also appears (with tree different concentrations in sublattices). The qualitative differences with the model considered on hypercubic lattices are also discussed.
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Affiliation(s)
- Konrad Jerzy Kapcia
- Faculty of Physics, Adam Mickiewicz University in Poznań, ulica Uniwersytetu Poznańskiego 2, PL-61614 Poznań, Poland
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Wu X, Ming F, Smith TS, Liu G, Ye F, Wang K, Johnston S, Weitering HH. Superconductivity in a Hole-Doped Mott-Insulating Triangular Adatom Layer on a Silicon Surface. PHYSICAL REVIEW LETTERS 2020; 125:117001. [PMID: 32976011 DOI: 10.1103/physrevlett.125.117001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/07/2020] [Indexed: 06/11/2023]
Abstract
Adsorption of one-third monolayer of Sn on an atomically clean Si(111) substrate produces a two-dimensional triangular adatom lattice with one unpaired electron per site. This dilute adatom reconstruction is an antiferromagnetic Mott insulator; however, the system can be modulation doped and metallized using heavily doped p-type Si(111) substrates. Here, we show that the hole-doped dilute adatom layer on a degenerately doped p-type Si(111) wafer is superconducting with a critical temperature of 4.7±0.3 K. While a phonon-mediated coupling scenario would be consistent with the observed T_{c}, Mott correlations in the Sn-derived dangling-bond surface state could suppress the s-wave pairing channel. The latter suggests that the superconductivity in this triangular adatom lattice may be unconventional.
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Affiliation(s)
- Xuefeng Wu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Fangfei Ming
- State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology and Guangdong Province Key Laboratory of Display Material and Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Tyler S Smith
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Guowei Liu
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Fei Ye
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Kedong Wang
- Department of Physics, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Steven Johnston
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
| | - Hanno H Weitering
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, Tennessee 37996, USA
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Adler F, Rachel S, Laubach M, Maklar J, Fleszar A, Schäfer J, Claessen R. Correlation-Driven Charge Order in a Frustrated Two-Dimensional Atom Lattice. PHYSICAL REVIEW LETTERS 2019; 123:086401. [PMID: 31491220 DOI: 10.1103/physrevlett.123.086401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/10/2019] [Indexed: 06/10/2023]
Abstract
We thoroughly examine the ground state of the triangular lattice of Pb on Si(111) using scanning tunneling microscopy and spectroscopy. We detect electronic charge order, and disentangle this contribution from the atomic configuration which we find to be 1-down-2-up, contrary to previous predictions from density functional theory. Applying an extended variational cluster approach we map out the phase diagram as a function of local and nonlocal Coulomb interactions. Comparing the experimental data with the theoretical modeling leads us to conclude that electron correlations are the driving force of the charge-ordered state in Pb/Si(111). These results resolve the discussion about the origin of the well-known 3×3 reconstruction. By exploiting the tunability of correlation strength, hopping parameters, and band filling, this material class represents a promising platform to search for exotic states of matter, in particular, for chiral topological superconductivity.
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Affiliation(s)
- F Adler
- Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - S Rachel
- School of Physics, University of Melbourne, Parkville, VIC 3010, Australia
- Institut für Theoretische Physik, Technische Universität Dresden, D-01069 Dresden, Germany
| | - M Laubach
- Institut für Theoretische Physik, Technische Universität Dresden, D-01069 Dresden, Germany
| | - J Maklar
- Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - A Fleszar
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg, Germany
| | - J Schäfer
- Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
| | - R Claessen
- Physikalisches Institut and Würzburg-Dresden Cluster of Excellence ct.qmat, Universität Würzburg, D-97074 Würzburg, Germany
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