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Ren H, Zhou J, Zhang A, Wu Z, Cai J, Fu X, Zhou J, Wan Z, Zhou B, Huang Y, Duan X. Precision Control of Amphoteric Doping in Cu x Bi 2Se 3 Nanoplates. PRECISION CHEMISTRY 2024; 2:421-427. [PMID: 39211432 PMCID: PMC11351425 DOI: 10.1021/prechem.4c00046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2024] [Revised: 07/10/2024] [Accepted: 07/15/2024] [Indexed: 09/04/2024]
Abstract
Copper-doped Bi2Se3 (Cu x Bi2Se3) is of considerable interest for tailoring its electronic properties and inducing exotic charge correlations while retaining the unique Dirac surface states. However, the copper dopants in Cu x Bi2Se3 display complex electronic behaviors and may function as either electron donors or acceptors depending on their concentration and atomic sites within the Bi2Se3 crystal lattice. Thus, a precise understanding and control of the doping concentration and sites is of both fundamental and practical significance. Herein, we report a solution-based one-pot synthesis of Cu x Bi2Se3 nanoplates with systematically tunable Cu doping concentrations and doping sites. Our studies reveal a gradual evolution from intercalative sites to substitutional sites with increasing Cu concentrations. The Cu atoms at intercalative sites function as electron donors while those at the substitutional sites function as electron acceptors, producing distinct effects on the electronic properties of the resulting materials. We further show that Cu0.18Bi2Se3 exhibits superconducting behavior, which is not present in Bi2Se3, highlighting the essential role of Cu doping in tailoring exotic quantum properties. This study establishes an efficient methodology for precise synthesis of Cu x Bi2Se3 with tailored doping concentrations, doping sites, and electronic properties.
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Affiliation(s)
- Huaying Ren
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jingxuan Zhou
- Department
of Materials Science and Engineering, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - Ao Zhang
- Department
of Materials Science and Engineering, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - Zixi Wu
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jin Cai
- Department
of Materials Science and Engineering, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - Xiaoyang Fu
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Jingyuan Zhou
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Zhong Wan
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
| | - Boxuan Zhou
- Department
of Materials Science and Engineering, University
of California, Los Angeles, Los
Angeles, California 90095, United States
| | - Yu Huang
- Department
of Materials Science and Engineering, University
of California, Los Angeles, Los
Angeles, California 90095, United States
- California
NanoSystems Institute, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Xiangfeng Duan
- Department
of Chemistry and Biochemistry, University
of California, Los Angeles, Los Angeles, California 90095, United States
- California
NanoSystems Institute, University of California,
Los Angeles, Los Angeles, California 90095, United States
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Wei XK, Jalil AR, Rüßmann P, Ando Y, Grützmacher D, Blügel S, Mayer J. Atomic Diffusion-Induced Polarization and Superconductivity in Topological Insulator-Based Heterostructures. ACS NANO 2024; 18:571-580. [PMID: 38126781 PMCID: PMC10786152 DOI: 10.1021/acsnano.3c08601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 12/23/2023]
Abstract
The proximity effect at a highly transparent interface of an s-wave superconductor (S) and a topological insulator (TI) provides a promising platform to create Majorana zero modes in artificially designed heterostructures. However, structural and chemical issues pertinent to such interfaces have been poorly explored so far. Here, we report the discovery of Pd diffusion-induced polarization at interfaces between superconductive Pd1+x(Bi0.4Te0.6)2 (xPBT, 0 ≤ x ≤ 1) and Pd-intercalated Bi2Te3 by using atomic-resolution scanning transmission electron microscopy. Our quantitative image analysis reveals that nanoscale lattice strain and QL polarity synergistically suppress and promote Pd diffusion at the normal and parallel interfaces, formed between Te-Pd-Bi triple layers (TLs) and Te-Bi-Te-Bi-Te quintuple layers (QLs), respectively. Further, our first-principles calculations unveil that the superconductivity of the xPBT phase and topological nature of the Pd-intercalated Bi2Te3 phase are robust against the broken inversion symmetry. These findings point out the necessity of considering the coexistence of electric polarization with superconductivity and topology in such S-TI systems.
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Affiliation(s)
- Xian-Kui Wei
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Abdur Rehman Jalil
- Peter
Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Philipp Rüßmann
- Institute
for Theoretical Physics and Astrophysics, University of Würzburg, 97074 Würzburg, Germany
- Peter
Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich GmbH and JARA, 52425 Jülich, Germany
| | - Yoichi Ando
- Physics
Institute II, University of Cologne, Zülpicher Straße 77, 50937 Köln, Germany
| | - Detlev Grützmacher
- Peter
Grünberg Institute and JARA-FIT, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - Stefan Blügel
- Peter
Grünberg Institute and Institute for Advanced Simulation, Forschungszentrum Jülich GmbH and JARA, 52425 Jülich, Germany
| | - Joachim Mayer
- Ernst
Ruska-Centre for Microscopy and Spectroscopy with Electrons, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
- Central
Facility for Electron Microscopy, RWTH Aachen
University, Ahornstraße
55, 52074 Aachen, Germany
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Jian SK, Huang Y, Yao H. Charge-4e Superconductivity from Nematic Superconductors in Two and Three Dimensions. PHYSICAL REVIEW LETTERS 2021; 127:227001. [PMID: 34889620 DOI: 10.1103/physrevlett.127.227001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 11/01/2021] [Indexed: 06/13/2023]
Abstract
Charge-4e superconductivity as a novel phase of matter remains elusive so far. Here, we show that charge-4e phase can arise as a vestigial order above the nematic superconducting transition temperature in time-reversal-invariant nematic superconductors. On the one hand, the nontrivial topological defect-nematic vortex-is energetically favored over the superconducting phase vortex when the nematic stiffness is less than the superfluid stiffness; consequently the charge-4e phase emerges by proliferation of nematic vortices upon increasing temperatures. On the other hand, the Ginzburg-Landau theory of the nematic superconductors has two distinct decoupling channels to either charge-4e orders or nematic orders; by analyzing the competition between the effective mass of the charge-4e order and the cubic potential of the nematic order, we find a sizable regime where the charge-4e order is favored. These two analyses consistently show that nematic superconductors can provide a promising route to realize charge-4e phases, which may apply to candidate nematic superconductors such as PbTaSe_{2} and twisted bilayer graphene.
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Affiliation(s)
- Shao-Kai Jian
- Condensed Matter Theory Center, Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Yingyi Huang
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
- School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Hong Yao
- Institute for Advanced Study, Tsinghua University, Beijing 100084, China
- State Key Laboratory of Low Dimensional Quantum Physics, Tsinghua University, Beijing 100084, China
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Kostylev I, Yonezawa S, Wang Z, Ando Y, Maeno Y. Uniaxial-strain control of nematic superconductivity in Sr xBi 2Se 3. Nat Commun 2020; 11:4152. [PMID: 32839435 PMCID: PMC7445267 DOI: 10.1038/s41467-020-17913-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 07/24/2020] [Indexed: 12/02/2022] Open
Abstract
Nematic states are characterized by rotational symmetry breaking without translational ordering. Recently, nematic superconductivity, in which the superconducting gap spontaneously lifts the rotational symmetry of the lattice, has been discovered. In nematic superconductivity, multiple superconducting domains with different nematic orientations can exist, and these domains can be controlled by a conjugate external stimulus. Domain engineering is quite common in magnets but has not been achieved in superconductors. Here, we report control of the nematic superconductivity and their domains of SrxBi2Se3, through externally-applied uniaxial stress. The suppression of subdomains indicates that it is the Δ4y state that is most favoured under compression along the basal Bi-Bi bonds. This fact allows us to determine the coupling parameter between the nematicity and lattice distortion. These results provide an inevitable step towards microscopic understanding and future utilization of the unique topological nematic superconductivity.
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Affiliation(s)
- Ivan Kostylev
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.
| | - Shingo Yonezawa
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan.
| | - Zhiwei Wang
- Institute of Physics II, University of Cologne, Köln, 50937, Germany
- Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement, Ministry of Education (MOE), School of Physics, Beijing Institute of Technology, Beijing, 100081, P. R. China
| | - Yoichi Ando
- Institute of Physics II, University of Cologne, Köln, 50937, Germany
| | - Yoshiteru Maeno
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto, 606-8502, Japan
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Li M, Fang Y, Pei C, Qi Y, Wang L. Phonon softening and higher-order anharmonic effect in the superconducting topological insulator Sr xBi 2Se 3. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:385701. [PMID: 32408275 DOI: 10.1088/1361-648x/ab9344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 05/14/2020] [Indexed: 06/11/2023]
Abstract
We report the anharmonic effect of the Raman-scattering spectrum in the low-carrier density superconductor SrxBi2Se3, which is dominated by the quartic term. Compared to the parent Bi2Se3, the superconducting SrxBi2Se3crystals show obvious phonon softening in the three optical phonon modesA1g1,Eg2, andA1g2. Based on the simulations by the Fano function, we present compelling evidence of the enhanced electron-phonon coupling in SrxBi2Se3for its smaller asymmetric parameterq. Moreover, an anomalous broadening and intensity antiresonance in the characteristic Raman peaks were observed as the temperature decreased to around 160 K. Thus, the superconducting topological material SrxBi2Se3represents a counterintuitive example where the electron-phonon interaction is strengthened by the accumulation of electron carriers.
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Affiliation(s)
- Mingtao Li
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China
| | - Yifei Fang
- Key Laboratory of High Power Laser Materials, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China
- Department of Physics, Fudan University, Shanghai 200433, People's Republic of China
| | - Cuiying Pei
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Yanpeng Qi
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, People's Republic of China
| | - Lin Wang
- Center for High Pressure Science and Technology Advanced Research, Shanghai 201203, People's Republic of China
- Center for High Pressure Science (CHIPS), State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, Hebei 066004, People's Republic of China
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Superconductivity in Cu Co-Doped Sr xBi 2Se 3 Single Crystals. MATERIALS 2019; 12:ma12233899. [PMID: 31779079 PMCID: PMC6926552 DOI: 10.3390/ma12233899] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Revised: 11/11/2019] [Accepted: 11/21/2019] [Indexed: 11/25/2022]
Abstract
In this study, we grew Cu co-doped single crystals of a topological superconductor candidate SrxBi2Se3, and studied their structural and transport properties. We reveal that the addition of even as small an amount of Cu co-dopant as 0.6 atomic %, completely suppresses superconductivity in SrxBi2Se3. Critical temperature (∼2.7 K) is rather robust with respect to co-doping. We show that Cu systematically increases the electron density and lattice parameters a and c. Our results demonstrate that superconductivity in SrxBi2Se3-based materials is induced by significantly lower Sr doping level x<0.02 than commonly accepted x∼0.06, and it strongly depends on the specific arrangement of Sr atoms in the host matrix. The critical temperature in superconductive Sr-doped Bi2Se3 is shown to be insensitive to carrier density.
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