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Kumar P, Kim H, Tripathy S, Watanabe K, Taniguchi T, Novoselov KS, Kotekar-Patil D. Excited state spectroscopy and spin splitting in single layer MoS 2 quantum dots. Nanoscale 2023; 15:18203-18211. [PMID: 37920920 DOI: 10.1039/d3nr03844k] [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] [Indexed: 11/04/2023]
Abstract
Semiconducting transition metal dichalcogenides (TMDCs) are very promising materials for quantum dots and spin-qubit implementation. Reliable operation of spin qubits requires the knowledge of the Landé g-factor, which can be measured by exploiting the discrete energy spectrum on a quantum dot. However, the quantum dots realized in TMDCs are yet to reach the required control and quality for reliable measurement of excited state spectroscopy and the g-factor, particularly in atomically thin layers. Quantum dot sizes reported in TMDCs so far are not small enough to observe discrete energy levels on them. Here, we report on electron transport through discrete energy levels of quantum dots in a single layer MoS2 isolated from its environment using a dual gate geometry. The quantum dot energy levels are separated by a few (5-6) meV such that the ground state and the first excited state transitions are clearly visible, thanks to the low contact resistance of ∼700 Ω and relatively low gate voltages. This well-resolved energy separation allowed us to accurately measure the ground state g-factor of ∼5 in MoS2 quantum dots. We observed a spin-filling sequence in our quantum dots under a perpendicular magnetic field. Such a system offers an excellent testbed to measure the key parameters for evaluation and implementation of spin-valley qubits in TMDCs, thus accelerating the development of quantum systems in two-dimensional semiconducting TMDCs.
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Affiliation(s)
- P Kumar
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, 117544, Singapore
- Integrative Sciences and Engineering Programme, National University of Singapore, 119077, Singapore
| | - H Kim
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Innovis, 2 Fusionopolis way, Singapore 138634, Singapore.
| | - S Tripathy
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Innovis, 2 Fusionopolis way, Singapore 138634, Singapore.
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials, Science, Tsukuba, 305-0044, Japan
| | - T Taniguchi
- Research Center for Functional Materials, National Institute for Materials, Science, Tsukuba, 305-0044, Japan
| | - K S Novoselov
- Institute for Functional Intelligent Materials, National University of Singapore, Singapore, 117544, Singapore
- Integrative Sciences and Engineering Programme, National University of Singapore, 119077, Singapore
- Department of Materials Science and Engineering, National University of Singapore, Singapore, 117575, Singapore.
| | - D Kotekar-Patil
- Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Innovis, 2 Fusionopolis way, Singapore 138634, Singapore.
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Kotekar-Patil D, Nguyen BM, Yoo J, Dayeh SA, Frolov SM. Quasiballistic quantum transport through Ge/Si core/shell nanowires. Nanotechnology 2017; 28:385204. [PMID: 28703121 DOI: 10.1088/1361-6528/aa7f82] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
We study signatures of ballistic quantum transport of holes through Ge/Si core/shell nanowires at low temperatures. We observe Fabry-Pérot interference patterns as well as conductance plateaus at integer multiples of 2e 2/h at zero magnetic field. Magnetic field evolution of these plateaus reveals relatively large effective Landé g-factors. Ballistic effects are observed in nanowires with silicon shell thickness of 1-3 nm, but not in bare germanium wires. These findings inform the future development of spin and topological quantum devices which rely on ballistic sub-band-resolved transport.
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Affiliation(s)
- D Kotekar-Patil
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
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Maurand R, Jehl X, Kotekar-Patil D, Corna A, Bohuslavskyi H, Laviéville R, Hutin L, Barraud S, Vinet M, Sanquer M, De Franceschi S. A CMOS silicon spin qubit. Nat Commun 2016; 7:13575. [PMID: 27882926 PMCID: PMC5123048 DOI: 10.1038/ncomms13575] [Citation(s) in RCA: 313] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 10/14/2016] [Indexed: 12/11/2022] Open
Abstract
Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot encoding a hole spin qubit, the second one a quantum dot used for the qubit read-out. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. The demonstrated qubit functionality in a basic transistor-like device constitutes a promising step towards the elaboration of scalable spin qubit geometries in a readily exploitable CMOS platform.
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Affiliation(s)
- R. Maurand
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
| | - X. Jehl
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
| | - D. Kotekar-Patil
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
| | - A. Corna
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
| | - H. Bohuslavskyi
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
| | - R. Laviéville
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - L. Hutin
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - S. Barraud
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - M. Vinet
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, LETI, MINATEC Campus, F-38054 Grenoble, France
| | - M. Sanquer
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
| | - S. De Franceschi
- University Grenoble Alpes, F-38000 Grenoble, France
- CEA, INAC-PHELIQS, F-38000 Grenoble, France
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Jehl X, Roche B, Sanquer M, Voisin B, Wacquez R, Deshpande V, Previtali B, Vinet M, Verduijn J, Tettamanzi G, Rogge S, Kotekar-Patil D, Ruoff M, Kern D, Wharam D, Belli M, Prati E, Fanciulli M. Mass Production of Silicon MOS-SETs: Can We Live with Nano-Devices’ Variability? ACTA ACUST UNITED AC 2011. [DOI: 10.1016/j.procs.2011.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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