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Li Y, Chan YH, Hlevyack JA, Bowers JW, Chou MY, Chiang TC. Topological Quantum Well States in Pb/Sb Thin-Film Heterostructures. ACS Nano 2024; 18:10243-10248. [PMID: 38530641 PMCID: PMC11008363 DOI: 10.1021/acsnano.4c00724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/12/2024] [Accepted: 03/21/2024] [Indexed: 03/28/2024]
Abstract
Composite topological heterostructures, wherein topologically protected states are electronically tuned due to their proximity to other matter, are key avenues for exploring emergent physical phenomena. Particularly, pairing a topological material with a superconductor such as Pb is a promising means for generating a topological superconducting phase with exotic Majorana quasiparticles, but oft-neglected is the emergence of bulklike spin-polarized states that are quite relevant to applications. Using high-resolution photoemission spectroscopy and first-principles calculations, we report the emergence of bulk-like spin-polarized topological quantum well states with long coherence lengths in Pb films grown on the topological semimetal Sb. The results establish Pb/Sb heterostructures as topological superconductor candidates and advance the current understanding of topological coupling effects required for realizing emergent physics and for designing advanced spintronic device architectures.
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Affiliation(s)
- Yao Li
- Department
of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois Urbana−Champaign; Urbana, Illinois 61801, United States
| | - Yang-hao Chan
- Institute
of Atomic and Molecular Sciences, Academia
Sinica, Taipei 10617, Taiwan
- Physics
Division, National Center for Theoretical
Sciences, Taipei 10617, Taiwan
| | - Joseph A. Hlevyack
- Department
of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois Urbana−Champaign; Urbana, Illinois 61801, United States
| | - John W. Bowers
- Department
of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois Urbana−Champaign; Urbana, Illinois 61801, United States
| | - Mei-Yin Chou
- Institute
of Atomic and Molecular Sciences, Academia
Sinica, Taipei 10617, Taiwan
- Department
of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Tai-Chang Chiang
- Department
of Physics and Frederick Seitz Materials Research Laboratory, University of Illinois Urbana−Champaign; Urbana, Illinois 61801, United States
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2
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Li Y, Bowers JW, Hlevyack JA, Lin MK, Chiang TC. Emergent and Tunable Topological Surface States in Complementary Sb/Bi 2Te 3 and Bi 2Te 3/Sb Thin-Film Heterostructures. ACS Nano 2022; 16:9953-9959. [PMID: 35699943 PMCID: PMC9245572 DOI: 10.1021/acsnano.2c04639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Epitaxial thin-film heterostructures offer a versatile platform for realizing topological surface states (TSSs) that may be emergent and/or tunable by tailoring the atomic layering in the heterostructures. Here, as an experimental demonstration, Sb and Bi2Te3 thin films with closely matched in-plane lattice constants are chosen to form two complementary heterostructures: Sb overlayers on Bi2Te3 (Sb/Bi2Te3) and Bi2Te3 overlayers on Sb (Bi2Te3/Sb), with the overlayer thickness as a tuning parameter. In the bulk form, Sb (a semimetal) and Bi2Te3 (an insulator) both host TSSs with the same topological order but substantially different decay lengths and dispersions, whereas ultrathin Sb and Bi2Te3 films by themselves are fully gapped trivial insulators. Angle-resolved photoemission band mappings, aided by theoretical calculations, confirm the formation of emergent TSSs in both heterostructures. The energy position of the topological Dirac point varies as a function of overlayer thickness, but the variation is non-monotonic, indicating nontrivial effects in the formation of topological heterostructure systems. The results illustrate the rich physics of engineered composite topological systems that may be exploited for nanoscale spintronics applications.
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Affiliation(s)
- Yao Li
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Frederick
Seitz Materials Research Laboratory, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - John W. Bowers
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Frederick
Seitz Materials Research Laboratory, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Joseph A. Hlevyack
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Frederick
Seitz Materials Research Laboratory, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Meng-Kai Lin
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Frederick
Seitz Materials Research Laboratory, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Department
of Physics, National Central University, Taoyuan 32001, Taiwan
| | - Tai-Chang Chiang
- Department
of Physics, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
- Frederick
Seitz Materials Research Laboratory, University
of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
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Abstract
A van der Waals bonded moiré bilayer formed by sequential growth of TiSe2 and TiTe2 monolayers exhibits emergent electronic structure as evidenced by angle-resolved photoemission band mapping. The two monolayers adopt the same lattice orientation but incommensurate lattice constants. Despite the lack of translational symmetry, sharp dispersive bands are observed. The dispersion relations appear distinct from those for the component monolayers alone. Theoretical calculations illustrate the formation of composite bands by coherent electronic coupling despite the weak interlayer bonding, which leads to band renormalization and energy shifts.
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Affiliation(s)
- Meng-Kai Lin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Tao He
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
| | - Joseph A Hlevyack
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Peng Chen
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, and Shanghai Center for Complex Physics, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Mei-Yin Chou
- Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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Lin MK, Hlevyack JA, Chen P, Liu RY, Mo SK, Chiang TC. Charge Instability in Single-Layer TiTe_{2} Mediated by van der Waals Bonding to Substrates. Phys Rev Lett 2020; 125:176405. [PMID: 33156647 DOI: 10.1103/physrevlett.125.176405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 09/10/2020] [Indexed: 06/11/2023]
Abstract
Single layers of transition metal dichalcogenides are of interest for emergent properties; an often-neglected issue is substrate effects. Our experiments show that the charge density wave in a single-layer TiTe_{2} grown on PtTe_{2} films is strongly suppressed by increasing the PtTe_{2} substrate thickness. Given that the interfacial bonding remains of the weak incommensurate van der Waals type, the observed changes are correlated with a thickness-dependent metallicity transformation in the PtTe_{2} substrate. The results illustrate the crucial role of the substrate in single-layer physics.
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Affiliation(s)
- Meng-Kai Lin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Joseph A Hlevyack
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Peng Chen
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science and Shanghai Center for Complex Physics, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ro-Ya Liu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Institute of Physics, Academia Sinica, Taipei 10617, Taiwan
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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5
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Hlevyack JA, Najafzadeh S, Lin MK, Hashimoto T, Nagashima T, Tsuzuki A, Fukushima A, Bareille C, Bai Y, Chen P, Liu RY, Li Y, Flötotto D, Avila J, Eckstein JN, Shin S, Okazaki K, Chiang TC. Massive Suppression of Proximity Pairing in Topological (Bi_{1-x}Sb_{x})_{2}Te_{3} Films on Niobium. Phys Rev Lett 2020; 124:236402. [PMID: 32603150 DOI: 10.1103/physrevlett.124.236402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 05/21/2020] [Indexed: 06/11/2023]
Abstract
Interfacing bulk conducting topological Bi_{2}Se_{3} films with s-wave superconductors initiates strong superconducting order in the nontrivial surface states. However, bulk insulating topological (Bi_{1-x}Sb_{x})_{2}Te_{3} films on bulk Nb instead exhibit a giant attenuation of surface superconductivity, even for films only two layers thick. This massive suppression of proximity pairing is evidenced by ultrahigh-resolution band mappings and by contrasting quantified superconducting gaps with those of heavily n-doped topological Bi_{2}Se_{3}/Nb. The results underscore the limitations of using superconducting proximity effects to realize topological superconductivity in nearly intrinsic systems.
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Affiliation(s)
- Joseph A Hlevyack
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Sahand Najafzadeh
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Meng-Kai Lin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Takahiro Hashimoto
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Tsubaki Nagashima
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Akihiro Tsuzuki
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Akiko Fukushima
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Cédric Bareille
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Yang Bai
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Peng Chen
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Shanghai Center for Complex Physics, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
- Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ro-Ya Liu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yao Li
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - David Flötotto
- Center for Soft Nanoscience, University of Münster, 48149 Münster, Germany
| | - José Avila
- Synchrotron SOLEIL and Université Paris-Saclay, L'Orme des Merisiers, BP48, 91190 Saint-Aubin, France
| | - James N Eckstein
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Shik Shin
- Office of University Professor, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Kozo Okazaki
- Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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6
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Lin MK, Villaos RAB, Hlevyack JA, Chen P, Liu RY, Hsu CH, Avila J, Mo SK, Chuang FC, Chiang TC. Dimensionality-Mediated Semimetal-Semiconductor Transition in Ultrathin PtTe_{2} Films. Phys Rev Lett 2020; 124:036402. [PMID: 32031832 DOI: 10.1103/physrevlett.124.036402] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Indexed: 06/10/2023]
Abstract
Platinum ditelluride (PtTe_{2}), a type-II Dirac semimetal, remains semimetallic in ultrathin films down to just two triatomic layers (TLs) with a negative gap of -0.36 eV. Further reduction of the film thickness to a single TL induces a Lifshitz electronic transition to a semiconductor with a large positive gap of +0.79 eV. This transition is evidenced by experimental band structure mapping of films prepared by layer-resolved molecular beam epitaxy, and by comparing the data to first-principles calculations using a hybrid functional. The results demonstrate a novel electronic transition at the two-dimensional limit through film thickness control.
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Affiliation(s)
- Meng-Kai Lin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | | | - Joseph A Hlevyack
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Peng Chen
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Shanghai Center for Complex Physics, School of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ro-Ya Liu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Institute of Physics, Academia Sinica, Taipei 10617, Taiwan
| | - Chia-Hsiu Hsu
- Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - José Avila
- Synchrotron SOLEIL and Universite Paris-Saclay, L'Orme des Merisiers, BP48, 91190 Saint-Aubin, France
| | - Sung-Kwan Mo
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Feng-Chuan Chuang
- Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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7
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Lin MK, Hlevyack JA, Chen P, Liu RY, Chiang TC. Comment on "Chiral Phase Transition in Charge Ordered 1T-TiSe_{2}". Phys Rev Lett 2019; 122:229701. [PMID: 31283261 DOI: 10.1103/physrevlett.122.229701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Indexed: 06/09/2023]
Affiliation(s)
- Meng-Kai Lin
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Joseph A Hlevyack
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Peng Chen
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ro-Ya Liu
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Institute of Physics, Academia Sinica, Taipei 10617, Taiwan
| | - T-C Chiang
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
- Frederick Seitz Materials Research Laboratory, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
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8
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Flötotto D, Bai Y, Chan YH, Chen P, Wang X, Rossi P, Xu CZ, Zhang C, Hlevyack JA, Denlinger JD, Hong H, Chou MY, Mittemeijer EJ, Eckstein JN, Chiang TC. In Situ Strain Tuning of the Dirac Surface States in Bi 2Se 3 Films. Nano Lett 2018; 18:5628-5632. [PMID: 30109804 DOI: 10.1021/acs.nanolett.8b02105] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Elastic strain has the potential for a controlled manipulation of the band gap and spin-polarized Dirac states of topological materials, which can lead to pseudomagnetic field effects, helical flat bands, and topological phase transitions. However, practical realization of these exotic phenomena is challenging and yet to be achieved. Here we show that the Dirac surface states of the topological insulator Bi2Se3 can be reversibly tuned by an externally applied elastic strain. Performing in situ X-ray diffraction and in situ angle-resolved photoemission spectroscopy measurements during tensile testing of epitaxial Bi2Se3 films bonded onto a flexible substrate, we demonstrate elastic strains of up to 2.1% and quantify the resulting changes in the topological surface state. Our study establishes the functional relationship between the lattice and electronic structures of Bi2Se3 and, more generally, demonstrates a new route toward momentum-resolved mapping of strain-induced band structure changes.
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Affiliation(s)
- David Flötotto
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Yang Bai
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Yang-Hao Chan
- Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
| | - Peng Chen
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Xiaoxiong Wang
- College of Science , Nanjing University of Science and Technology , Nanjing 210094 , China
| | - Paul Rossi
- Max Planck Institute for Intelligent Systems , Heisenbergstraße 3 , D-70569 Stuttgart , Germany
| | - Cai-Zhi Xu
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Can Zhang
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Joseph A Hlevyack
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Jonathan D Denlinger
- Advanced Light Source , Lawrence Berkeley National Laboratory , Berkeley , California 94720 , United States
| | - Hawoong Hong
- Advanced Photon Source , Argonne National Laboratory , Argonne , Illinois 60439 , United States
| | - Mei-Yin Chou
- Institute of Atomic and Molecular Sciences , Academia Sinica , Taipei 10617 , Taiwan
- School of Physics , Georgia Institute of Technology , Atlanta , Georgia 30332 , United States
- Department of Physics , National Taiwan University , Taipei 10617 , Taiwan
| | - Eric J Mittemeijer
- Max Planck Institute for Intelligent Systems , Heisenbergstraße 3 , D-70569 Stuttgart , Germany
- Institute for Materials Science , University of Stuttgart , Germany
| | - James N Eckstein
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Tai-Chang Chiang
- Department of Physics , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Frederick Seitz Materials Research Laboratory , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
- Department of Physics , National Taiwan University , Taipei 10617 , Taiwan
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