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Xia J, Gu Y, Mai J, Hu T, Wang Q, Xie C, Wu Y, Wang X. Tuneable Schottky contact of MoSi2N4/ TaS2 van der Waals heterostructure. Heliyon 2023; 9:e20619. [PMID: 37867820 PMCID: PMC10589790 DOI: 10.1016/j.heliyon.2023.e20619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/02/2023] [Accepted: 10/02/2023] [Indexed: 10/24/2023] Open
Abstract
The two-dimensional M o S i 2 N 4 monolayer is an emerging semiconductor material that offers considerable promise due to its ultra-thin profile, tuneable mechanical properties, excellent optoelectronic properties and exceptional environmental stability. The van der Waals (vdW) heterostructure formed by stacking such two-dimensional monolayers has demonstrated superior performance across various domains. In this study, a vdW heterostructure combining the two-dimensional M o S i 2 N 4 and T a S 2 monolayers is examined using first-principles density functional theory. In its ground state, this van der Waals heterostructure establishes an ohmic contact with an exceptionally low potential barrier height. By modulating the vdW heterostructure with an applied electric field of -0.1 V/Å and under vertical stress, we discovered that M o S i 2 N 4 and T a S 2 can transition from an ohmic contact to a p-type Schottky with an ultra-low Schottky barrier height (SBH). Our observations may give valuable insights for designing reconfigurable, tuneable Schottky nano-devices with enhanced electronic and optical properties based on M o S i 2 N 4 / T a S 2 .
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Affiliation(s)
- Jinglin Xia
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Yixiao Gu
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Jun Mai
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Tianyang Hu
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Qikun Wang
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Chao Xie
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Yunkai Wu
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
| | - Xu Wang
- Key Laboratory of Electronic Composites of Guizhou Province, College of Big Data and Information Engineering, Guizhou University, Guiyang 550025, Guizhou, People's Republic of China
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Accurate graphene quantum Hall arrays for the new International System of Units. Nat Commun 2022; 13:6933. [PMID: 36376308 PMCID: PMC9663594 DOI: 10.1038/s41467-022-34680-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 11/02/2022] [Indexed: 11/16/2022] Open
Abstract
Graphene quantum Hall effect (QHE) resistance standards have the potential to provide superior realizations of three key units in the new International System of Units (SI): the ohm, the ampere, and the kilogram (Kibble Balance). However, these prospects require different resistance values than practically achievable in single graphene devices (~12.9 kΩ), and they need bias currents two orders of magnitude higher than typical breakdown currents IC ~ 100 μA. Here we present experiments on quantization accuracy of a 236-element quantum Hall array (QHA), demonstrating RK/236 ≈ 109 Ω with 0.2 part-per-billion (nΩ/Ω) accuracy with IC ≥ 5 mA (~1 nΩ/Ω accuracy for IC = 8.5 mA), using epitaxial graphene on silicon carbide (epigraphene). The array accuracy, comparable to the most precise universality tests of QHE, together with the scalability and reliability of this approach, pave the road for wider use of graphene in the new SI and beyond. The 2019 redefinition of the International System of Units requires a 100 Ω quantum resistance standard for the ideal electrical realization of the kilogram via the Kibble Balance. Here, the authors report the realization of an array of 236 graphene quantum Hall bars, demonstrating a quantized resistance of 109 Ω with an accuracy of 0.2 nΩ/Ω over an extended range of bias currents.
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Hao Y, Zhang G, Liu D, Liu DE. Anomalous universal conductance as a hallmark of non-locality in a Majorana-hosted superconducting island. Nat Commun 2022; 13:6699. [PMID: 36335121 PMCID: PMC9637197 DOI: 10.1038/s41467-022-34437-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 10/25/2022] [Indexed: 11/07/2022] Open
Abstract
The non-local feature of topological states of matter is the key for the topological protection of quantum information and enables robust non-local manipulation in quantum information. Here we propose to manifest the non-local feature of a Majorana-hosted superconducting island by measuring the temperature dependence of Coulomb blockade peak conductance in different regimes. In the low-temperature regime, we discover a coherent double Majorana-assisted teleportation (MT) process, where any independent tunneling process always involves two coherent non-local MTs; and we also find an anomalous universal scaling behavior, i.e., a crossover from a \documentclass[12pt]{minimal}
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\begin{document}$${[\max (T,eV)]}^{3}$$\end{document}[max(T,eV)]3 power-law conductance behavior when energy scale increases — in stark contrast to the usual exponential suppression due to certain local transport. In the high-temperature regime, the conductance is instead proportional to the temperature inverse, indicating a non-monotonic temperature-dependence of the conductance. Both the anomalous power law and non-monotonic temperature-dependence of the conductance can be distinguished from the conductance peak in the traditional Coulomb block, and therefore, together serve as a hallmark for the non-local feature in the Majorana-hosted superconducting island. The ability to detect the non-local nature of topological states in electron transport is highly desirable for topological quantum computation. Hao et al. propose a two-terminal transport scheme to detect the non-locality of a topological superconducting island via anomalous scaling of the tunnelling conductance.
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Affiliation(s)
- Yiru Hao
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, 100084, Beijing, China.,Frontier Science Center for Quantum Information, 100184, Beijing, China
| | - Gu Zhang
- Beijing Academy of Quantum Information Sciences, 100193, Beijing, China
| | - Donghao Liu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, 100084, Beijing, China
| | - Dong E Liu
- State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, 100084, Beijing, China. .,Frontier Science Center for Quantum Information, 100184, Beijing, China. .,Beijing Academy of Quantum Information Sciences, 100193, Beijing, China.
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Rathore S, Patel DK, Thakur MK, Haider G, Kalbac M, Kruskopf M, Liu CI, Rigosi AF, Elmquist RE, Liang CT, Hong PD. Highly sensitive broadband binary photoresponse in gateless epitaxial graphene on 4H-SiC. CARBON 2021; 184:10.1016/j.carbon.2021.07.098. [PMID: 37200678 PMCID: PMC10190169 DOI: 10.1016/j.carbon.2021.07.098] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Due to weak light-matter interaction, standard chemical vapor deposition (CVD)/exfoliated single-layer graphene-based photodetectors show low photoresponsivity (on the order of mA/W). However, epitaxial graphene (EG) offers a more viable approach for obtaining devices with good photoresponsivity. EG on 4H-SiC also hosts an interfacial buffer layer (IBL), which is the source of electron carriers applicable to quantum optoelectronic devices. We utilize these properties to demonstrate a gate-free, planar EG/4H-SiC-based device that enables us to observe the positive photoresponse for (405-532) nm and negative photoresponse for (632-980) nm laser excitation. The broadband binary photoresponse mainly originates from the energy band alignment of the IBL/EG interface and the highly sensitive work function of the EG. We find that the photoresponsivity of the device is > 10 A/W under 405 nm of power density 7.96 mW/cm2 at 1 V applied bias, which is three orders of magnitude greater than the obtained values of CVD/exfoliated graphene and higher than the required value for practical applications. These results path the way for selective light-triggered logic devices based on EG and can open a new window for broadband photodetection.
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Affiliation(s)
- Shivi Rathore
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, 106335, Taiwan
| | - Dinesh Kumar Patel
- Department of Physics, National Taiwan University, Taipei, 106319, Taiwan
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg MD, 20899, USA
| | - Mukesh Kumar Thakur
- J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague 8, Czech Republic
| | - Golam Haider
- J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague 8, Czech Republic
- Corresponding author. (G. Haider)
| | - Martin Kalbac
- J. Heyrovsky Institute of Physical Chemistry, Czech Academy of Sciences, Prague 8, Czech Republic
| | - Mattias Kruskopf
- Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, D-38116, Braunschweig, Germany
| | - Chieh-I Liu
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg MD, 20899, USA
- Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, 20742, USA
| | - Albert F. Rigosi
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg MD, 20899, USA
| | - Randolph E. Elmquist
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg MD, 20899, USA
| | - Chi-Te Liang
- Department of Physics, National Taiwan University, Taipei, 106319, Taiwan
- Corresponding author. (C.-T. Liang)
| | - Po-Da Hong
- Department of Materials Science and Engineering, National Taiwan University of Science and Technology, Taipei, 106335, Taiwan
- Corresponding author. (P.-D. Hong)
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Hu IF, Panna AR, Rigosi AF, Kruskopf M, Patel DK, Liu CI, Saha D, Payagala SU, Newell DB, Jarrett DG, Liang CT, Elmquist RE. Onsager-Casimir frustration from resistance anisotropy in graphene quantum Hall devices. PHYSICAL REVIEW. B 2021; 104:10.1103/physrevb.104.085418. [PMID: 36875776 PMCID: PMC9982844 DOI: 10.1103/physrevb.104.085418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
We report on nonreciprocity observations in several configurations of graphene-based quantum Hall devices. Two distinct measurement configurations were adopted to verify the universality of the observations (i.e., two-terminal arrays and four-terminal devices). Our findings determine the extent to which epitaxial graphene anisotropies contribute to the observed asymmetric Hall responses. The presence of backscattering induces a device-dependent asymmetry rendering the Onsager-Casimir relations limited in their capacity to describe the behavior of such devices, except in the low-field classical regime and the fully quantized Hall state. The improved understanding of this quantum electrical process broadly limits the applicability of the reciprocity principle in the presence of quantum phase transitions and for anisotropic two-dimensional materials.
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Affiliation(s)
- I-Fan Hu
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Alireza R. Panna
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - Albert F. Rigosi
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - Mattias Kruskopf
- Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig, Germany
| | - Dinesh K. Patel
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Chieh-I Liu
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
- Department of Chemistry and Biochemistry, University of Maryland, College Park, Maryland 20742, USA
| | - Dipanjan Saha
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - Shamith U. Payagala
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - David B. Newell
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - Dean G. Jarrett
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
| | - Chi-Te Liang
- Department of Physics, National Taiwan University, Taipei 10617, Taiwan
| | - Randolph E. Elmquist
- Physical Measurement Laboratory, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland 20899, USA
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