1
|
Gao H, Kong ZZ, Zhang P, Luo Y, Su H, Liu XF, Wang GL, Wang JY, Xu HQ. Gate-defined quantum point contacts in a germanium quantum well. NANOSCALE 2024; 16:10333-10339. [PMID: 38738596 DOI: 10.1039/d4nr00712c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2024]
Abstract
We report an experimental study of quantum point contacts defined in a high-quality strained germanium quantum well with layered electric gates. At a zero magnetic field, we observed quantized conductance plateaus in units of 2e2/h. Bias-spectroscopy measurements reveal that the energy spacing between successive one-dimensional subbands ranges from 1.5 to 5 meV as a consequence of the small effective mass of the holes and the narrow gate constrictions. At finite magnetic fields perpendicular to the device plane, the edges of the conductance plateaus get split due to the Zeeman effect and Landé g factors were estimated to be ∼6.6 for the holes in the germanium quantum well. We demonstrate that all quantum point contacts in the same device have comparable performances, indicating a reliable and reproducible device fabrication process. Thus, our work lays a foundation for investigating multiple forefronts of physics in germanium-based quantum devices that require quantum point contacts as building blocks.
Collapse
Affiliation(s)
- Han Gao
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
| | - Zhen-Zhen Kong
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
| | - Po Zhang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| | - Yi Luo
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
- Institute of Condensed Matter and Material Physics, School of Physics, Peking University, Beijing 100871, China
| | - Haitian Su
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
- Institute of Condensed Matter and Material Physics, School of Physics, Peking University, Beijing 100871, China
| | - Xiao-Fei Liu
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| | - Gui-Lei Wang
- Key Laboratory of Microelectronics Devices & Integrated Technology, Institute of Microelectronics, Chinese Academy of Sciences, Beijing 100029, China.
- Hefei National Laboratory, University of Science and Technology of China, Hefei, Anhui 230088, China
- Beijing Superstring Academy of Memory Technology, Beijing 100176, China
| | - Ji-Yin Wang
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| | - H Q Xu
- Beijing Key Laboratory of Quantum Devices, Key Laboratory for the Physics and Chemistry of Nanodevices, and School of Electronics, Peking University, Beijing 100871, China.
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
| |
Collapse
|
2
|
Myronov M, Kycia J, Waldron P, Jiang W, Barrios P, Bogan A, Coleridge P, Studenikin S. Holes Outperform Electrons in Group IV Semiconductor Materials. SMALL SCIENCE 2023. [DOI: 10.1002/smsc.202200094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023] Open
Affiliation(s)
- Maksym Myronov
- Physics Department The University of Warwick Coventry CV4 7AL UK
| | - Jan Kycia
- Physics and Astronomy Department University of Waterloo Waterloo N2L 3G1 Canada
| | - Philip Waldron
- Security and Disruptive Technologies Research Centre National Research Council of Canada Ottawa K1A 0R6 Ontario Canada
| | - Weihong Jiang
- Security and Disruptive Technologies Research Centre National Research Council of Canada Ottawa K1A 0R6 Ontario Canada
| | - Pedro Barrios
- Security and Disruptive Technologies Research Centre National Research Council of Canada Ottawa K1A 0R6 Ontario Canada
| | - Alex Bogan
- Security and Disruptive Technologies Research Centre National Research Council of Canada Ottawa K1A 0R6 Ontario Canada
| | - Peter Coleridge
- Security and Disruptive Technologies Research Centre National Research Council of Canada Ottawa K1A 0R6 Ontario Canada
| | - Sergei Studenikin
- Security and Disruptive Technologies Research Centre National Research Council of Canada Ottawa K1A 0R6 Ontario Canada
| |
Collapse
|
3
|
Hendrickx NW, Lawrie WIL, Petit L, Sammak A, Scappucci G, Veldhorst M. A single-hole spin qubit. Nat Commun 2020; 11:3478. [PMID: 32651363 PMCID: PMC7351715 DOI: 10.1038/s41467-020-17211-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 06/16/2020] [Indexed: 11/09/2022] Open
Abstract
Qubits based on quantum dots have excellent prospects for scalable quantum technology due to their compatibility with standard semiconductor manufacturing. While early research focused on the simpler electron system, recent demonstrations using multi-hole quantum dots illustrated the favourable properties holes can offer for fast and scalable quantum control. Here, we establish a single-hole spin qubit in germanium and demonstrate the integration of single-shot readout and quantum control. We deplete a planar germanium double quantum dot to the last hole, confirmed by radio-frequency reflectrometry charge sensing. To demonstrate the integration of single-shot readout and qubit operation, we show Rabi driving on both qubits. We find remarkable electric control over the qubit resonance frequencies, providing great qubit addressability. Finally, we analyse the spin relaxation time, which we find to exceed one millisecond, setting the benchmark for hole quantum dot qubits. The ability to coherently manipulate a single hole spin underpins the quality of strained germanium and defines an excellent starting point for the construction of quantum hardware. While most results so far in semiconductor spin-based quantum computation use electron spins, devices based on hole spins may have more favourable properties for quantum applications. Here, the authors demonstrate single-shot readout and coherent control of a qubit made from a single hole spin.
Collapse
Affiliation(s)
- N W Hendrickx
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands.
| | - W I L Lawrie
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands
| | - L Petit
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands
| | - A Sammak
- QuTech and Netherlands Organisation for Applied Scientific Research (TNO), Stieltjesweg 1, 2628 CK, Delft, The Netherlands
| | - G Scappucci
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands
| | - M Veldhorst
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, P. O. Box 5046, 2600 GA, Delft, The Netherlands.
| |
Collapse
|
4
|
Hardy WJ, Harris CT, Su YH, Chuang Y, Moussa J, Maurer LN, Li JY, Lu TM, Luhman DR. Single and double hole quantum dots in strained Ge/SiGe quantum wells. NANOTECHNOLOGY 2019; 30:215202. [PMID: 30869078 DOI: 10.1088/1361-6528/ab061e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Even as today's most prominent spin-based qubit technologies are maturing in terms of capability and sophistication, there is growing interest in exploring alternate material platforms that may provide advantages, such as enhanced qubit control, longer coherence times, and improved extensibility. Recent advances in heterostructure material growth have opened new possibilities for employing hole spins in semiconductors for qubit applications. Undoped, strained Ge/SiGe quantum wells are promising candidate hosts for hole spin-based qubits due to their low disorder, large intrinsic spin-orbit coupling strength, and absence of valley states. Here, we use a simple one-layer gated device structure to demonstrate both a single quantum dot as well as coupling between two adjacent quantum dots. The hole effective mass in these undoped structures, m* ∼ 0.08 m 0, is significantly lower than for electrons in Si/SiGe, pointing to the possibility of enhanced tunnel couplings in quantum dots and favorable qubit-qubit interactions in an industry-compatible semiconductor platform.
Collapse
Affiliation(s)
- Will J Hardy
- Sandia National Laboratories, Albuquerque, NM 87123, United States of America
| | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Vigneau F, Mizokuchi R, Zanuz DC, Huang X, Tan S, Maurand R, Frolov S, Sammak A, Scappucci G, Lefloch F, De Franceschi S. Germanium Quantum-Well Josephson Field-Effect Transistors and Interferometers. NANO LETTERS 2019; 19:1023-1027. [PMID: 30633528 DOI: 10.1021/acs.nanolett.8b04275] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Hybrid superconductor-semiconductor structures attract increasing attention owing to a variety of potential applications in quantum computing devices. They can serve the realization of topological superconducting systems as well as gate-tunable superconducting quantum bits. Here, we combine a SiGe/Ge/SiGe quantum-well heterostructure hosting high-mobility two-dimensional holes and aluminum superconducting leads to realize prototypical hybrid devices, such as Josephson field-effect transistors (JoFETs) and superconducting quantum interference devices (SQUIDs). We observe gate-controlled supercurrent transport with Ge channels as long as one micrometer and estimate the induced superconducting gap from tunnel spectroscopy measurements. Transmission electron microscopy reveals the diffusion of Ge into the Al contacts, whereas no Al is detected in the Ge channel.
Collapse
Affiliation(s)
- Florian Vigneau
- Université Grenoble Alpes, CEA, INAC-Pheliqs , 38000 Grenoble , France
| | - Raisei Mizokuchi
- Université Grenoble Alpes, CEA, INAC-Pheliqs , 38000 Grenoble , France
| | - Dante Colao Zanuz
- Université Grenoble Alpes, CEA, INAC-Pheliqs , 38000 Grenoble , France
| | - Xuhai Huang
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
| | - Susheng Tan
- Department of Electrical and Computer Engineering and Petersen Institute of NanoScience and Engineering , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
| | - Romain Maurand
- Université Grenoble Alpes, CEA, INAC-Pheliqs , 38000 Grenoble , France
| | - Sergey Frolov
- Department of Physics and Astronomy , University of Pittsburgh , Pittsburgh , Pennsylvania 15260 , United States
| | - Amir Sammak
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology Lorentzweg 1 , 2628 CJ Delft , The Netherlands
- QuTech and TNO , Stieltjesweg 1 , 2628 CK Delft , The Netherlands
| | - Giordano Scappucci
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology Lorentzweg 1 , 2628 CJ Delft , The Netherlands
| | - Francois Lefloch
- Université Grenoble Alpes, CEA, INAC-Pheliqs , 38000 Grenoble , France
| | | |
Collapse
|
6
|
Overweg H, Knothe A, Fabian T, Linhart L, Rickhaus P, Wernli L, Watanabe K, Taniguchi T, Sánchez D, Burgdörfer J, Libisch F, Fal'ko VI, Ensslin K, Ihn T. Topologically Nontrivial Valley States in Bilayer Graphene Quantum Point Contacts. PHYSICAL REVIEW LETTERS 2018; 121:257702. [PMID: 30608777 DOI: 10.1103/physrevlett.121.257702] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Indexed: 06/09/2023]
Abstract
We present measurements of quantized conductance in electrostatically induced quantum point contacts in bilayer graphene. The application of a perpendicular magnetic field leads to an intricate pattern of lifted and restored degeneracies with increasing field: at zero magnetic field the degeneracy of quantized one-dimensional subbands is four, because of a twofold spin and a twofold valley degeneracy. By switching on the magnetic field, the valley degeneracy is lifted. Because of the Berry curvature, states from different valleys split linearly in magnetic field. In the quantum Hall regime fourfold degenerate conductance plateaus reemerge. During the adiabatic transition to the quantum Hall regime, levels from one valley shift by two in quantum number with respect to the other valley, forming an interweaving pattern that can be reproduced by numerical calculations.
Collapse
Affiliation(s)
- Hiske Overweg
- Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Angelika Knothe
- National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Thomas Fabian
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria
| | - Lukas Linhart
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria
| | - Peter Rickhaus
- Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Lucien Wernli
- Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Kenji Watanabe
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- National Institute for Material Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - David Sánchez
- Institute for Cross-Disciplinary Physics and Complex Systems IFISC (UIB-CSIC), 07122 Palma de Mallorca, Spain
| | - Joachim Burgdörfer
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria
| | - Florian Libisch
- Institute for Theoretical Physics, Vienna University of Technology, A-1040 Vienna, Austria
| | - Vladimir I Fal'ko
- National Graphene Institute, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Klaus Ensslin
- Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Thomas Ihn
- Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich, Switzerland
| |
Collapse
|