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Liang X, Shamim S, Chen D, Fürst L, Taniguchi T, Watanabe K, Buhmann H, Kleinlein J, Molenkamp LW. Graphite/h-BN van der Waals heterostructure as a gate stack for HgTe quantum wells. NANOTECHNOLOGY 2024; 35:345001. [PMID: 38788703 DOI: 10.1088/1361-6528/ad501c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Accepted: 05/24/2024] [Indexed: 05/26/2024]
Abstract
Two-dimensional topological insulators have attracted much interest due to their potential applications in spintronics and quantum computing. To access the exotic physical phenomena, a gate electric field is required to tune the Fermi level into the bulk band gap. Hexagonal boron nitride (h-BN) is a promising alternative gate dielectric due to its unique advantages such as flat and charge-free surface. Here we present a h-BN/graphite van der Waals heterostructure as a top gate on HgTe heterostructure-based Hall bar devices. We compare our results to devices with h-BN/Ti/Au and HfO2/Ti/Au gates. Devices with a h-BN/graphite gate show no charge carrier density shift compared to as-grown structures, in contrast to a significant n-type carrier density increase for HfO2/Ti/Au. We attribute this observation mainly to the comparable work function of HgTe and graphite. In addition, devices with h-BN gate dielectric show slightly higher electron mobility compared to HfO2-based devices. Our results demonstrate the compatibility between layered materials transfer and wet-etched structures and provide a strategy to solve the issue of significant shifts of the carrier density in gated HgTe heterostructures.
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Affiliation(s)
- Xianhu Liang
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
| | - Saquib Shamim
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
| | - Dongyun Chen
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
| | - Lena Fürst
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Hartmut Buhmann
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
| | - Johannes Kleinlein
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
| | - Laurens W Molenkamp
- Physikalisches Institut (EP3), Universität Würzburg, 97074 Würzburg, Germany
- Institute for Topological Insulators, 97074 Würzburg, Germany
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Zhou T, Dartiailh MC, Sardashti K, Han JE, Matos-Abiague A, Shabani J, Žutić I. Fusion of Majorana bound states with mini-gate control in two-dimensional systems. Nat Commun 2022; 13:1738. [PMID: 35365644 PMCID: PMC8976011 DOI: 10.1038/s41467-022-29463-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 03/16/2022] [Indexed: 11/09/2022] Open
Abstract
A hallmark of topological superconductivity is the non-Abelian statistics of Majorana bound states (MBS), its chargeless zero-energy emergent quasiparticles. The resulting fractionalization of a single electron, stored nonlocally as a two spatially-separated MBS, provides a powerful platform for implementing fault-tolerant topological quantum computing. However, despite intensive efforts, experimental support for MBS remains indirect and does not probe their non-Abelian statistics. Here we propose how to overcome this obstacle in mini-gate controlled planar Josephson junctions (JJs) and demonstrate non-Abelian statistics through MBS fusion, detected by charge sensing using a quantum point contact, based on dynamical simulations. The feasibility of preparing, manipulating, and fusing MBS in two-dimensional (2D) systems is supported in our experiments which demonstrate the gate control of topological transition and superconducting properties with five mini gates in InAs/Al-based JJs. While we focus on this well-established platform, where the topological superconductivity was already experimentally detected, our proposal to identify elusive non-Abelian statistics motivates also further MBS studies in other gate-controlled 2D systems.
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Affiliation(s)
- Tong Zhou
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA.
| | - Matthieu C Dartiailh
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Kasra Sardashti
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Jong E Han
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA
| | - Alex Matos-Abiague
- Department of Physics and Astronomy, Wayne State University, Detroit, MI, 48201, USA
| | - Javad Shabani
- Center for Quantum Phenomena, Department of Physics, New York University, New York, NY, 10003, USA
| | - Igor Žutić
- Department of Physics, University at Buffalo, State University of New York, Buffalo, NY, 14260, USA.
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Chen X, Ju M, Song K, Chen G, Yang R, Wang J. Synthesis of hierarchical MoSe 2 nanolayers on sodium sulfide crystals for electrocatalytic hydrogen evolution. CrystEngComm 2021. [DOI: 10.1039/d1ce00831e] [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
Largely hierarchical MoSe2 nanolayers were successfully prepared by easily removable water solubility sodium sulfide and displayed outstanding HER properties.
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Affiliation(s)
- Xiaoshuang Chen
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, P. R. China
- Heilongjiang Provincial Key Laboratory of Surface Active Agent and Auxiliary, Qiqihar 161006, P. R. China
| | - Meina Ju
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, P. R. China
| | - Kun Song
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, P. R. China
| | - Guoli Chen
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, P. R. China
| | - Rui Yang
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, P. R. China
- Heilongjiang Provincial Key Laboratory of Surface Active Agent and Auxiliary, Qiqihar 161006, P. R. China
| | - Jinping Wang
- College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006, P. R. China
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