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Fukumoto K, Lee S, Adachi SI, Suzuki Y, Kusakabe K, Yamamoto R, Kitatani M, Ishida K, Nakagawa Y, Merkel M, Shiga D, Kumigashira H. Surface terminations control charge transfer from bulk to surface states in topological insulators. Sci Rep 2024; 14:10537. [PMID: 38719934 PMCID: PMC11079079 DOI: 10.1038/s41598-024-61172-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 05/02/2024] [Indexed: 05/12/2024] Open
Abstract
Topological insulators (TI) hold significant potential for various electronic and optoelectronic devices that rely on the Dirac surface state (DSS), including spintronic and thermoelectric devices, as well as terahertz detectors. The behavior of electrons within the DSS plays a pivotal role in the performance of such devices. It is expected that DSS appear on a surface of three dimensional(3D) TI by mechanical exfoliation. However, it is not always the case that the surface terminating atomic configuration and corresponding band structures are homogeneous. In order to investigate the impact of surface terminating atomic configurations on electron dynamics, we meticulously examined the electron dynamics at the exfoliated surface of a crystalline 3D TI (Bi2 Se3 ) with time, space, and energy resolutions. Based on our comprehensive band structure calculations, we found that on one of the Se-terminated surfaces, DSS is located within the bulk band gap, with no other surface states manifesting within this region. On this particular surface, photoexcited electrons within the conduction band effectively relax towards DSS and tend to linger at the Dirac point for extended periods of time. It is worth emphasizing that these distinct characteristics of DSS are exclusively observed on this particular surface.
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Affiliation(s)
- Keiki Fukumoto
- High energy accelerator research organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan.
| | - Seunghee Lee
- High energy accelerator research organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Shin-Ichi Adachi
- High energy accelerator research organization (KEK), 1-1 Oho, Tsukuba, Ibaraki, 305-0801, Japan
| | - Yuta Suzuki
- The Graduate University for Advanced Studies (SOKENDAI), Hayama, Kanagawa, 240-0193, Japan
| | - Koichi Kusakabe
- University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan
| | - Rikuto Yamamoto
- University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan
| | - Motoharu Kitatani
- University of Hyogo, 3-2-1 Kouto, Kamigori-cho, Ako-gun, Hyogo, 678-1297, Japan
| | - Kunio Ishida
- Utsunomiya University, 7-1-2 Yoto, Utsunomiya, Tochigi, 321-8585, Japan
| | | | - Michael Merkel
- FOCUS GmbH, Neukirchner Str.2, 65510, Huenstetten, Germany
| | - Daisuke Shiga
- Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
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2
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Jia T, Yang L, Zhang J, Kimura H, Zhao H, Guo Q, Cheng Z. Piezoelectricity of Bi 2Se 3 Nanosheet. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2504. [PMID: 37764533 PMCID: PMC10535138 DOI: 10.3390/nano13182504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 08/29/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023]
Abstract
Bi2Se3, one of the most extensively studied topological insulators, has received significant attention, and abundant research has been dedicated to exploring its surface electronic properties. However, little attention has been given to its piezoelectric properties. Herein, we investigate the piezoelectric response in a five-layer Bi2Se3 nanosheet using scanning probe microscopy (SPM) techniques. The piezoelectricity of Bi2Se3 is characterized using both conventional piezoresponse force microscopy (PFM) and a sequential excitation scanning probe microscopy (SE-SPM) technique. To confirm the linear piezoelectricity of Bi2Se3 two-dimensional materials, measurements of point-wise linear and quadratic electromechanical responses are carried out. Furthermore, the presence of polarization and relaxation is confirmed through hysteresis loops. As expected, the Bi2Se3 nanosheet exhibits an electromechanical solid response. Due to the inevitable loss of translational symmetry at the crystal edge, the lattice of the odd-layer Bi2Se3 nanosheet is noncentrosymmetric, indicating its potential for linear piezoelectricity. This research holds promise for nanoelectromechanical systems (NEMS) applications and future nanogenerators.
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Affiliation(s)
- Tingting Jia
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China;
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Liu Yang
- Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
| | - Juncheng Zhang
- Optics and Optoelectronics Laboratory, Department of Physics, Ocean University of China, Qingdao 266100, China
| | - Hideo Kimura
- School of Environmental and Material Engineering, Yantai University, Yantai 264005, China
| | - Hongyang Zhao
- Hubei Key Laboratory of Plasma Chemistry and Advanced Materials, Department of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, China
| | - Quansheng Guo
- School of Materials Science and Engineering, Hubei University, Wuhan 430062, China;
| | - Zhenxiang Cheng
- Institute for Superconducting & Electronic Materials, University of Wollongong, Innovation Campus, Wollongong, NSW 2500, Australia
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3
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Influence of ZnS crystal morphology on adsorption-photocatalytic efficiency of pseudocrystal ZnS nanomaterials for methylene blue degradation. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132514] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Kawasaki JK, Sharan A, Johansson LIM, Hjort M, Timm R, Thiagarajan B, Schultz BD, Mikkelsen A, Janotti A, Palmstrøm CJ. A simple electron counting model for half-Heusler surfaces. SCIENCE ADVANCES 2018; 4:eaar5832. [PMID: 29868642 PMCID: PMC5983916 DOI: 10.1126/sciadv.aar5832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/20/2018] [Indexed: 06/08/2023]
Abstract
Heusler compounds are a ripe platform for discovery and manipulation of emergent properties in topological and magnetic heterostructures. In these applications, the surfaces and interfaces are critical to performance; however, little is known about the atomic-scale structure of Heusler surfaces and interfaces or why they reconstruct. Using a combination of molecular beam epitaxy, core-level and angle-resolved photoemission, scanning tunneling microscopy, and density functional theory, we map the phase diagram and determine the atomic and electronic structures for several surface reconstructions of CoTiSb (001), a prototypical semiconducting half-Heusler. At low Sb coverage, the surface is characterized by Sb-Sb dimers and Ti vacancies, while, at high Sb coverage, an adlayer of Sb forms. The driving forces for reconstruction are charge neutrality and minimizing the number of Sb dangling bonds, which form metallic surface states within the bulk bandgap. We develop a simple electron counting model that explains the atomic and electronic structure, as benchmarked against experiments and first-principles calculations. We then apply the model to explain previous experimental observations at other half-Heusler surfaces, including the topological semimetal PtLuSb and the half-metallic ferromagnet NiMnSb. The model provides a simple framework for understanding and predicting the surface structure and properties of these novel quantum materials.
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Affiliation(s)
- Jason K. Kawasaki
- Department of Materials Science and Engineering, University of Wisconsin–Madison, Madison WI 53706, USA
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Abhishek Sharan
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
| | - Linda I. M. Johansson
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Nanometer Structure Consortium, Lund University, Lund, Sweden
| | - Martin Hjort
- Division of Synchrotron Radiation Research and Nanometer Structure Consortium, Lund University, Lund, Sweden
| | - Rainer Timm
- Division of Synchrotron Radiation Research and Nanometer Structure Consortium, Lund University, Lund, Sweden
| | | | - Brian D. Schultz
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
| | - Anders Mikkelsen
- Division of Synchrotron Radiation Research and Nanometer Structure Consortium, Lund University, Lund, Sweden
| | - Anderson Janotti
- Department of Physics and Astronomy, University of Delaware, Newark, DE 19716, USA
- Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716, USA
| | - Chris J. Palmstrøm
- Materials Department, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
- Department of Electrical and Computer Engineering, University of California, Santa Barbara, Santa Barbara, CA 93106, USA
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Rusinov IP, Golub P, Sklyadneva IY, Isaeva A, Menshchikova TV, Echenique PM, Chulkov EV. Chemically driven surface effects in polar intermetallic topological insulators A3Bi. Phys Chem Chem Phys 2018; 20:26372-26385. [PMID: 30303503 DOI: 10.1039/c8cp04016h] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Surface electronic spectra, surface and bulk properties as well as the underlying chemical bonding characteristics in topological insulators with complex bonding patterns are considered for the example of cubic, polar intermetallics KNa2Bi, K3Bi and Rb3Bi (with the general formula A3Bi, A – alkali metal).
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Affiliation(s)
- I. P. Rusinov
- Tomsk State University
- Tomsk
- Russia
- St. Petersburg State University
- St. Petersburg
| | - P. Golub
- National University of Singapore
- 117575 Singapore
- Singapore
| | - I. Yu. Sklyadneva
- Tomsk State University
- Tomsk
- Russia
- Karlsruher Institut für Technologie
- Institut für Festkörperphysik
| | - A. Isaeva
- Technische Universität Dresden
- Dresden
- Germany
| | | | - P. M. Echenique
- Donostia International Physics Center (DIPC)
- 20018 San Sebastián/Donostia
- Spain
- Departamento de Física de Materiales
- Facultad de Ciencias Químicas
| | - E. V. Chulkov
- Tomsk State University
- Tomsk
- Russia
- St. Petersburg State University
- St. Petersburg
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Lee P, Kim J, Kim JG, Ryu MT, Park HM, Kim N, Kim Y, Lee NS, Kioussis N, Jhi SH, Chung J. Topological modification of the electronic structure by Bi-bilayers lying deep inside bulk Bi₂Se₃. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:085002. [PMID: 26852742 DOI: 10.1088/0953-8984/28/8/085002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We observe the modified surface states of an epitaxial thin film of a homologous series of (Bi2)m(Bi2Se3)n, as a topological insulator (TI), by angle-resolved photoemission spectroscopy measurements. A thin film with m : n = 1 : 3 (Bi8Se9) has been grown with Bi2 bilayers embedded every other three quintuple layers (QLs) of Bi2Se3. Despite the reduced dimension of continuous QLs due to the Bi2 heterolayers, we find that the topological surface states stem from the inverted Bi and Se states and the topologically nontrivial structures are mainly based on the prototype of 3D TI Bi2Se3 without affecting the overall topological order.
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Affiliation(s)
- Paengro Lee
- Department of Physics, Pohang University of Science and Technology, Pohang 790-784, Korea
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7
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Exceptional surface and bulk electronic structures in a topological insulator, Bi2Se3. Sci Rep 2015; 5:17351. [PMID: 26644075 PMCID: PMC4672339 DOI: 10.1038/srep17351] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 10/29/2015] [Indexed: 11/08/2022] Open
Abstract
The outstanding problem in topological insulators is the bulk metallicity underneath topologically ordered surface states and the appearance of Dirac point far away from the Fermi energy. Enormous efforts are being devoted to get the Dirac point at the Fermi level via exposure to foreign materials so that these materials can be used in technology and realize novel fundamental physics. Ironically, the conclusion of bulk metallicity in the electronic structure is essentially based on the angle resolved photoemission spectroscopy, a highly surface sensitive technique. Here, we employed state-of-the-art hard x-ray photoemission spectroscopy with judiciously chosen experiment geometry to delineate the bulk electronic structure of a topological insulator and a potential thermoelectric material, Bi2Se3. The results exhibit signature of insulating bulk electronic structure with tiny intensities at akin to defect/vacancy induced doped states in the semiconductors. The core level spectra exhibit intense plasmon peak associated to core level excitations manifesting the signature of coupling of electrons to the collective excitations, a possible case of plasmon-phonon coupling. In addition, a new loss feature appear in the core level spectra indicating presence of additional collective excitations in the system.
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8
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Politano A, Silkin VM, Nechaev IA, Vitiello MS, Viti L, Aliev ZS, Babanly MB, Chiarello G, Echenique PM, Chulkov EV. Interplay of Surface and Dirac Plasmons in Topological Insulators: The Case of Bi_{2}Se_{3}. PHYSICAL REVIEW LETTERS 2015; 115:216802. [PMID: 26636863 DOI: 10.1103/physrevlett.115.216802] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2015] [Indexed: 06/05/2023]
Abstract
We have investigated plasmonic excitations at the surface of Bi_{2}Se_{3}(0001) via high-resolution electron energy loss spectroscopy. For low parallel momentum transfer q_{∥}, the loss spectrum shows a distinctive feature peaked at 104 meV. This mode varies weakly with q_{∥}. The behavior of its intensity as a function of primary energy and scattering angle indicates that it is a surface plasmon. At larger momenta (q_{∥}~0.04 Å^{-1}), an additional peak, attributed to the Dirac plasmon, becomes clearly defined in the loss spectrum. Momentum-resolved loss spectra provide evidence of the mutual interaction between the surface plasmon and the Dirac plasmon of Bi_{2}Se_{3}. The proposed theoretical model accounting for the coexistence of three-dimensional doping electrons and two-dimensional Dirac fermions accurately represents the experimental observations. The results reveal novel routes for engineering plasmonic devices based on topological insulators.
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Affiliation(s)
- A Politano
- Department of Physics, University of Calabria, 87036 Rende (CS), Italy
| | - V M Silkin
- Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Spain
- Departamento de Física de Materiales, Universidad del País Vasco, Apartado 1072, 20080 San Sebastián/Donostia, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| | - I A Nechaev
- Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Spain
- Tomsk State University, 634050 Tomsk, Russian Federation
- Saint Petersburg State University, 198504 Saint Petersburg, Russian Federation
| | - M S Vitiello
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - L Viti
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, 56127 Pisa, Italy
| | - Z S Aliev
- Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Spain
- Institute of Catalysis and Inorganic Chemistry, ANAS, AZ1143 Baku, Azerbaijian
- Institute of Physics, ANAS, AZ1143 Baku, Azerbaijian
| | - M B Babanly
- Institute of Catalysis and Inorganic Chemistry, ANAS, AZ1143 Baku, Azerbaijian
| | - G Chiarello
- Department of Physics, University of Calabria, 87036 Rende (CS), Italy
- CNISM, Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Via della Vasca Navale, 84, 00146 Roma, Italy
| | - P M Echenique
- Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Spain
- Departamento de Física de Materiales, Universidad del País Vasco, Apartado 1072, 20080 San Sebastián/Donostia, Spain
- Centro de Física de Materiales CFM-Materials Physics Center MPC, Centro Mixto CSIC-UPV/EHU, Paseo de Manuel Lardizabal 5, 20018 San Sebastián/Donostia, Spain
| | - E V Chulkov
- Donostia International Physics Center (DIPC), Paseo de Manuel Lardizabal 4, 20018 San Sebastián/Donostia, Spain
- Departamento de Física de Materiales, Universidad del País Vasco, Apartado 1072, 20080 San Sebastián/Donostia, Spain
- Tomsk State University, 634050 Tomsk, Russian Federation
- Saint Petersburg State University, 198504 Saint Petersburg, Russian Federation
- Centro de Física de Materiales CFM-Materials Physics Center MPC, Centro Mixto CSIC-UPV/EHU, Paseo de Manuel Lardizabal 5, 20018 San Sebastián/Donostia, Spain
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Biswas D, Thakur S, Ali K, Balakrishnan G, Maiti K. Anomalies of a topologically ordered surface. Sci Rep 2015; 5:10260. [PMID: 26041405 PMCID: PMC4455236 DOI: 10.1038/srep10260] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 04/07/2015] [Indexed: 11/30/2022] Open
Abstract
Bulk insulators with strong spin orbit coupling exhibit metallic surface states possessing topological order protected by the time reversal symmetry. However, experiments show vulnerability of topological states to aging and impurities. Different studies show contrasting behavior of the Dirac states along with plethora of anomalies, which has become an outstanding problem in material science. Here, we probe the electronic structure of Bi2Se3 employing high resolution photoemission spectroscopy and discover the dependence of the behavior of Dirac particles on surface terminations. The Dirac cone apex appears at different binding energies and exhibits contrasting shift on Bi and Se terminated surfaces with complex time dependence emerging from subtle adsorbed oxygen-surface atom interactions. These results uncover the surface states behavior of real systems and the dichotomy of topological and normal surface states important for device fabrication as well as realization of novel physics such as Majorana Fermions, magnetic monopole, etc.
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Affiliation(s)
- Deepnarayan Biswas
- Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India
| | - Sangeeta Thakur
- Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India
| | - Khadiza Ali
- Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India
| | | | - Kalobaran Maiti
- Department of Condensed Matter Physics and Materials' Science, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai - 400 005, India
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