1
|
Wang IH, Chiu YW, Lin HC, Li PW. Transport diagrams of germanium double quantum dots/Si barriers using photocurrent measurement. Sci Rep 2024; 14:20749. [PMID: 39237567 PMCID: PMC11377824 DOI: 10.1038/s41598-024-71177-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Accepted: 08/26/2024] [Indexed: 09/07/2024] Open
Abstract
We reported transport diagrams of self-assembled germanium (Ge) double quantum-dots (DQDs) using direct current measurement under illumination at wavelength (λ) of 850 nm and at the base temperature of 4.5 K. Ge DQDs with a coupling-barrier of Si, tunneling-barriers of Si3N4, and self-aligned p+-Si reservoirs were fabricated in a self-organized CMOS approach. Charge transport through the Ge-DQDs is facilitated by photon-assisted tunneling. Characteristic gate-controlled hexagonal-shaped cells over a wide range of hole occupancy are acquired thanks to hard-wall confinement. Large dimensions (ΔVG > 200 mV) of hexagonal-shaped cells are favored for the operation of charge states, indicating that our Ge DQDs system is less susceptible to shot noises arising from external voltage sources. Estimated intra-QD and inter-QD charging energies are EC,R/EC,L = 48.9 meV/42.7 meV and ECm = 7.8 meV, respectively.
Collapse
Affiliation(s)
- I-Hsiang Wang
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsin-chu, Taiwan
| | - Yu-Wen Chiu
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsin-chu, Taiwan
| | - Horng-Chih Lin
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsin-chu, Taiwan
| | - Pei-Wen Li
- Institute of Electronics, National Yang Ming Chiao Tung University, Hsin-chu, Taiwan.
| |
Collapse
|
2
|
Badawy G, Bakkers EPAM. Electronic Transport and Quantum Phenomena in Nanowires. Chem Rev 2024; 124:2419-2440. [PMID: 38394689 PMCID: PMC10941195 DOI: 10.1021/acs.chemrev.3c00656] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 01/26/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024]
Abstract
Nanowires are natural one-dimensional channels and offer new opportunities for advanced electronic quantum transport experiments. We review recent progress on the synthesis of nanowires and methods for the fabrication of hybrid semiconductor/superconductor systems. We discuss methods to characterize their electronic properties in the context of possible future applications such as topological and spin qubits. We focus on group III-V (InAs and InSb) and group IV (Ge/Si) semiconductors, since these are the most developed, and give an outlook on other potential materials.
Collapse
Affiliation(s)
- Ghada Badawy
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| | - Erik P. A. M. Bakkers
- Department of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, The Netherlands
| |
Collapse
|
3
|
Jin IK, Kumar K, Rendell MJ, Huang JY, Escott CC, Hudson FE, Lim WH, Dzurak AS, Hamilton AR, Liles SD. Combining n-MOS Charge Sensing with p-MOS Silicon Hole Double Quantum Dots in a CMOS platform. NANO LETTERS 2023; 23:1261-1266. [PMID: 36748989 DOI: 10.1021/acs.nanolett.2c04417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Holes in silicon quantum dots are receiving attention due to their potential as fast, tunable, and scalable qubits in semiconductor quantum circuits. Despite this, challenges remain in this material system including difficulties using charge sensing to determine the number of holes in a quantum dot, and in controlling the coupling between adjacent quantum dots. We address these problems by fabricating an ambipolar complementary metal-oxide-semiconductor (CMOS) device using multilayer palladium gates. The device consists of an electron charge sensor adjacent to a hole double quantum dot. We demonstrate control of the spin state via electric dipole spin resonance. We achieve smooth control of the interdot coupling rate over 1 order of magnitude and use the charge sensor to perform spin-to-charge conversion to measure the hole singlet-triplet relaxation time of 11 μs for a known hole occupation. These results provide a path toward improving the quality and controllability of hole spin-qubits.
Collapse
Affiliation(s)
- Ik Kyeong Jin
- School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Krittika Kumar
- School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Matthew J Rendell
- School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Jonathan Yue Huang
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
- Diraq, Sydney, New South Wales 2052, Australia
| | - Chris C Escott
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
- Diraq, Sydney, New South Wales 2052, Australia
| | - Fay E Hudson
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
- Diraq, Sydney, New South Wales 2052, Australia
| | - Wee Han Lim
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
- Diraq, Sydney, New South Wales 2052, Australia
| | - Andrew S Dzurak
- School of Electrical Engineering and Telecommunications, The University of New South Wales, Sydney, New South Wales 2052, Australia
- Diraq, Sydney, New South Wales 2052, Australia
| | - Alexander R Hamilton
- School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Scott D Liles
- School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia
| |
Collapse
|
4
|
DFT Analysis of Hole Qubits Spin State in Germanium Thin Layer. NANOMATERIALS 2022; 12:nano12132244. [PMID: 35808079 PMCID: PMC9268541 DOI: 10.3390/nano12132244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/18/2022] [Accepted: 06/27/2022] [Indexed: 02/01/2023]
Abstract
Due to the presence of a strong spin–orbit interaction, hole qubits in germanium are increasingly being considered as candidates for quantum computing. These objects make it possible to create electrically controlled logic gates with the basic properties of scalability, a reasonable quantum error correction, and the necessary speed of operation. In this paper, using the methods of quantum-mechanical calculations and considering the non-collinear magnetic interactions, the quantum states of the system 2D structure of Ge in the presence of even and odd numbers of holes were investigated. The spatial localizations of hole states were calculated, favorable quantum states were revealed, and the magnetic structural characteristics of the system were analyzed.
Collapse
|
5
|
Alfieri A, Anantharaman SB, Zhang H, Jariwala D. Nanomaterials for Quantum Information Science and Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022:e2109621. [PMID: 35139247 DOI: 10.1002/adma.202109621] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 02/04/2022] [Indexed: 06/14/2023]
Abstract
Quantum information science and engineering (QISE)-which entails the use of quantum mechanical states for information processing, communications, and sensing-and the area of nanoscience and nanotechnology have dominated condensed matter physics and materials science research in the 21st century. Solid-state devices for QISE have, to this point, predominantly been designed with bulk materials as their constituents. This review considers how nanomaterials (i.e., materials with intrinsic quantum confinement) may offer inherent advantages over conventional materials for QISE. The materials challenges for specific types of qubits, along with how emerging nanomaterials may overcome these challenges, are identified. Challenges for and progress toward nanomaterials-based quantum devices are condidered. The overall aim of the review is to help close the gap between the nanotechnology and quantum information communities and inspire research that will lead to next-generation quantum devices for scalable and practical quantum applications.
Collapse
Affiliation(s)
- Adam Alfieri
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Surendra B Anantharaman
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Huiqin Zhang
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Deep Jariwala
- Electrical and Systems Engineering, University of Pennsylvania, Philadelphia, PA, 19104, USA
| |
Collapse
|
6
|
Ultrafast coherent control of a hole spin qubit in a germanium quantum dot. Nat Commun 2022; 13:206. [PMID: 35017522 PMCID: PMC8752786 DOI: 10.1038/s41467-021-27880-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 12/16/2021] [Indexed: 11/23/2022] Open
Abstract
Operation speed and coherence time are two core measures for the viability of a qubit. Strong spin-orbit interaction (SOI) and relatively weak hyperfine interaction make holes in germanium (Ge) intriguing candidates for spin qubits with rapid, all-electrical coherent control. Here we report ultrafast single-spin manipulation in a hole-based double quantum dot in a germanium hut wire (GHW). Mediated by the strong SOI, a Rabi frequency exceeding 540 MHz is observed at a magnetic field of 100 mT, setting a record for ultrafast spin qubit control in semiconductor systems. We demonstrate that the strong SOI of heavy holes (HHs) in our GHW, characterized by a very short spin-orbit length of 1.5 nm, enables the rapid gate operations we accomplish. Our results demonstrate the potential of ultrafast coherent control of hole spin qubits to meet the requirement of DiVincenzo’s criteria for a scalable quantum information processor. Hole-spin qubits in germanium are promising candidates for rapid, all-electrical qubit control. Here the authors report Rabi oscillations with the record frequency of 540 MHz in a hole-based double quantum dot in a germanium hut wire, which is attributed to strong spin-orbit interaction of heavy holes.
Collapse
|
7
|
Zhang T, Liu H, Gao F, Xu G, Wang K, Zhang X, Cao G, Wang T, Zhang J, Hu X, Li HO, Guo GP. Anisotropic g-Factor and Spin-Orbit Field in a Germanium Hut Wire Double Quantum Dot. NANO LETTERS 2021; 21:3835-3842. [PMID: 33914549 DOI: 10.1021/acs.nanolett.1c00263] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Holes in nanowires have drawn significant attention in recent years because of the strong spin-orbit interaction, which plays an important role in constructing Majorana zero modes and manipulating spin-orbit qubits. Here, from the strongly anisotropic leakage current in the spin blockade regime for a double dot, we extract the full g-tensor and find that the spin-orbit field is in plane with an azimuthal angle of 59° to the axis of the nanowire. The direction of the spin-orbit field indicates a strong spin-orbit interaction along the nanowire, which may have originated from the interface inversion asymmetry in Ge hut wires. We also demonstrate two different spin relaxation mechanisms for the holes in the Ge hut wire double dot: spin-flip co-tunneling to the leads, and spin-orbit interaction within the double dot. These results help establish feasibility of a Ge-based quantum processor.
Collapse
Affiliation(s)
- Ting Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - He Liu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Fei Gao
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Gang Xu
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ke Wang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Xin Zhang
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Gang Cao
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Ting Wang
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Jianjun Zhang
- Institute of Physics and CAS Center for Excellence in Topological Quantum Computation, Chinese Academy of Sciences, Beijing 100190, China
| | - Xuedong Hu
- Department of Physics, University at Buffalo, SUNY, Buffalo, New York 14260, United States
| | - Hai-Ou Li
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Guo-Ping Guo
- CAS Key Laboratory of Quantum Information, University of Science and Technology of China, Hefei, Anhui 230026, China
- CAS Center for Excellence and Synergetic Innovation Center in Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Origin Quantum Computing Company Limited, Hefei, Anhui 230026, China
| |
Collapse
|
8
|
Froning FNM, Camenzind LC, van der Molen OAH, Li A, Bakkers EPAM, Zumbühl DM, Braakman FR. Ultrafast hole spin qubit with gate-tunable spin-orbit switch functionality. NATURE NANOTECHNOLOGY 2021; 16:308-312. [PMID: 33432204 DOI: 10.1038/s41565-020-00828-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
Quantum computers promise to execute complex tasks exponentially faster than any possible classical computer, and thus spur breakthroughs in quantum chemistry, material science and machine learning. However, quantum computers require fast and selective control of large numbers of individual qubits while maintaining coherence. Qubits based on hole spins in one-dimensional germanium/silicon nanostructures are predicted to experience an exceptionally strong yet electrically tunable spin-orbit interaction, which allows us to optimize qubit performance by switching between distinct modes of ultrafast manipulation, long coherence and individual addressability. Here we used millivolt gate voltage changes to tune the Rabi frequency of a hole spin qubit in a germanium/silicon nanowire from 31 to 219 MHz, its driven coherence time between 7 and 59 ns, and its Landé g-factor from 0.83 to 1.27. We thus demonstrated spin-orbit switch functionality, with on/off ratios of roughly seven, which could be further increased through improved gate design. Finally, we used this control to optimize our qubit further and approach the strong driving regime, with spin-flipping times as short as ~1 ns.
Collapse
Affiliation(s)
| | | | - Orson A H van der Molen
- University of Basel, Basel, Switzerland
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Ang Li
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, the Netherlands
| | - Erik P A M Bakkers
- Department of Applied Physics, Eindhoven University of Technology, Eindhoven, the Netherlands
| | | | | |
Collapse
|
9
|
Ghirri A, Cornia S, Affronte M. Microwave Photon Detectors Based on Semiconducting Double Quantum Dots. SENSORS (BASEL, SWITZERLAND) 2020; 20:s20144010. [PMID: 32707648 PMCID: PMC7412044 DOI: 10.3390/s20144010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 07/01/2020] [Accepted: 07/15/2020] [Indexed: 05/14/2023]
Abstract
Detectors of microwave photons find applications in different fields ranging from security to cosmology. Due to the intrinsic difficulties related to the detection of vanishingly small energy quanta ℏ ω , significant portions of the microwave electromagnetic spectrum are still uncovered by suitable techniques. No prevailing technology has clearly emerged yet, although different solutions have been tested in different contexts. Here, we focus on semiconductor quantum dots, which feature wide tunability by external gate voltages and scalability for large architectures. We discuss possible pathways for the development of microwave photon detectors based on photon-assisted tunneling in semiconducting double quantum dot circuits. In particular, we consider implementations based on either broadband transmission lines or resonant cavities, and we discuss how developments in charge sensing techniques and hybrid architectures may be beneficial for the development of efficient photon detectors in the microwave range.
Collapse
Affiliation(s)
- Alberto Ghirri
- Istituto Nanoscienze-CNR, via Campi 213/a, 41125 Modena, Italy; (S.C.); (M.A.)
- Correspondence:
| | - Samuele Cornia
- Istituto Nanoscienze-CNR, via Campi 213/a, 41125 Modena, Italy; (S.C.); (M.A.)
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, via Campi 213/a, 41125 Modena, Italy
| | - Marco Affronte
- Istituto Nanoscienze-CNR, via Campi 213/a, 41125 Modena, Italy; (S.C.); (M.A.)
- Dipartimento di Scienze Fisiche, Informatiche e Matematiche, Università di Modena e Reggio Emilia, via Campi 213/a, 41125 Modena, Italy
| |
Collapse
|
10
|
Aryal S, Pati R. Spin filtering with Mn-doped Ge-core/Si-shell nanowires. NANOSCALE ADVANCES 2020; 2:1843-1849. [PMID: 36132517 PMCID: PMC9416944 DOI: 10.1039/c9na00803a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 02/27/2020] [Indexed: 06/12/2023]
Abstract
Incorporating spin functionality into a semiconductor core-shell nanowire that offers immunity from the substrate effect is a highly desirable step for its application in next generation spintronics. Here, using first-principles density functional theory that does not make any assumptions of the electronic structure, we predict that a very small amount of Mn dopants in the core region of the wire can transform the Ge-Si core-shell semiconductor nanowire into a half-metallic ferromagnet that is stable at room temperature. The energy band structures reveal a semiconducting behavior for one spin direction while the metallic behavior for the other, indicating 100% spin polarization at the Fermi energy. No measurable shifts in energy levels in the vicinity of Fermi energy are found due to spin-orbit coupling, which suggests that the spin coherence length can be much higher in this material. To further assess the use of this material in a practical device setting, we have used a quantum transport approach to calculate the spin-filtering efficiency for a channel made out of a finite nanowire segment. Our calculations yield an efficiency more than 90%, which further confirms the excellent spin-selective properties of our newly tailored Mn-doped Ge-core/Si-shell nanowires.
Collapse
Affiliation(s)
- Sandip Aryal
- Department of Physics, Michigan Technological University Houghton MI 49931 USA
| | - Ranjit Pati
- Department of Physics, Michigan Technological University Houghton MI 49931 USA
| |
Collapse
|
11
|
Crippa A, Ezzouch R, Aprá A, Amisse A, Laviéville R, Hutin L, Bertrand B, Vinet M, Urdampilleta M, Meunier T, Sanquer M, Jehl X, Maurand R, De Franceschi S. Gate-reflectometry dispersive readout and coherent control of a spin qubit in silicon. Nat Commun 2019; 10:2776. [PMID: 31270319 PMCID: PMC6610084 DOI: 10.1038/s41467-019-10848-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 05/22/2019] [Indexed: 11/11/2022] Open
Abstract
Silicon spin qubits have emerged as a promising path to large-scale quantum processors. In this prospect, the development of scalable qubit readout schemes involving a minimal device overhead is a compelling step. Here we report the implementation of gate-coupled rf reflectometry for the dispersive readout of a fully functional spin qubit device. We use a p-type double-gate transistor made using industry-standard silicon technology. The first gate confines a hole quantum dot encoding the spin qubit, the second one a helper dot enabling readout. The qubit state is measured through the phase response of a lumped-element resonator to spin-selective interdot tunneling. The demonstrated qubit readout scheme requires no coupling to a Fermi reservoir, thereby offering a compact and potentially scalable solution whose operation may be extended above 1 K.
Collapse
Affiliation(s)
- A Crippa
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France.
| | - R Ezzouch
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France
| | - A Aprá
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France
| | - A Amisse
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France
| | - R Laviéville
- CEA, LETI, Minatec Campus, F-38000, Grenoble, France
| | - L Hutin
- CEA, LETI, Minatec Campus, F-38000, Grenoble, France
| | - B Bertrand
- CEA, LETI, Minatec Campus, F-38000, Grenoble, France
| | - M Vinet
- CEA, LETI, Minatec Campus, F-38000, Grenoble, France
| | - M Urdampilleta
- CNRS, Grenoble INP, Institut Néel, University of Grenoble Alpes, F-38000, Grenoble, France
| | - T Meunier
- CNRS, Grenoble INP, Institut Néel, University of Grenoble Alpes, F-38000, Grenoble, France
| | - M Sanquer
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France
| | - X Jehl
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France
| | - R Maurand
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France.
| | - S De Franceschi
- CEA, INAC-PHELIQS, University of Grenoble Alpes, F-38000, Grenoble, France
| |
Collapse
|
12
|
Wang R, Deacon RS, Sun J, Yao J, Lieber CM, Ishibashi K. Gate Tunable Hole Charge Qubit Formed in a Ge/Si Nanowire Double Quantum Dot Coupled to Microwave Photons. NANO LETTERS 2019; 19:1052-1060. [PMID: 30636426 DOI: 10.1021/acs.nanolett.8b04343] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
A controllable and coherent light-matter interface is an essential element for a scalable quantum information processor. Strong coupling to an on-chip cavity has been accomplished in various electron quantum dot systems, but rarely explored in the hole systems. Here we demonstrate a hybrid architecture comprising a microwave transmission line resonator controllably coupled to a hole charge qubit formed in a Ge/Si core/shell nanowire (NW), which is a natural one-dimensional hole gas with a strong spin-orbit interaction (SOI) and lack of nuclear spin scattering, potentially enabling fast spin manipulation by electric manners and long coherence times. The charge qubit is established in a double quantum dot defined by local electrical gates. Qubit transition energy can be independently tuned by the electrochemical potential difference and the tunnel coupling between the adjacent dots, opening transverse (σ x) and longitudinal (σ z) degrees of freedom for qubit operation and interaction. As the qubit energy is swept across the photon level, the coupling with resonator is thus switched on and off, as detected by resonator transmission spectroscopy. The observed resonance dynamics is replicated by a complete quantum numerical simulation considering an efficient charge dipole-photon coupling with a strength up to 2π × 55 MHz, yielding an estimation of the spin-resonator coupling rate through SOI to be about 10 MHz. The results inspire the future researches on the coherent hole-photon interaction in Ge/Si nanowires.
Collapse
Affiliation(s)
- Rui Wang
- Advanced Device Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Department of Physics , Tokyo University of Science , Kagurazaka, Tokyo 162-8601 , Japan
| | - Russell S Deacon
- Advanced Device Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Center for Emergent Matter Science (CEMS) , RIKEN , Wako , Saitama 351-0198 , Japan
| | - Jian Sun
- Advanced Device Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Hunan Key Laboratory of Super Micro-Structure and Ultrafast Process, School of Physics and Electronics , Central South University , Changsha 410083 , China
| | - Jun Yao
- Department of Electrical and Computer Engineering, Institute for Applied Life Sciences , University of Massachusetts , Amherst , Massachusetts 01003 , United States
| | - Charles M Lieber
- Deparment of Chemistry and Chemical Biology , Harvard University , Cambridge , Massachusetts 02138 , United States
- School of Engineering and Applied Sciences , Harvard University , Cambridge , Massachusetts 02138 , United States
| | - Koji Ishibashi
- Advanced Device Laboratory , RIKEN , Wako , Saitama 351-0198 , Japan
- Center for Emergent Matter Science (CEMS) , RIKEN , Wako , Saitama 351-0198 , Japan
| |
Collapse
|
13
|
Ridderbos J, Brauns M, Shen J, de Vries FK, Li A, Bakkers EPAM, Brinkman A, Zwanenburg FA. Josephson Effect in a Few-Hole Quantum Dot. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1802257. [PMID: 30260519 DOI: 10.1002/adma.201802257] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/11/2018] [Indexed: 06/08/2023]
Abstract
A Ge-Si core-shell nanowire is used to realize a Josephson field-effect transistor with highly transparent contacts to superconducting leads. By changing the electric field, access to two distinct regimes, not combined before in a single device, is gained: in the accumulation mode the device is highly transparent and the supercurrent is carried by multiple subbands, while near depletion, the supercurrent is carried by single-particle levels of a strongly coupled quantum dot operating in the few-hole regime. These results establish Ge-Si nanowires as an important platform for hybrid superconductor-semiconductor physics and Majorana fermions.
Collapse
Affiliation(s)
- Joost Ridderbos
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Matthias Brauns
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Jie Shen
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands
| | - Folkert K de Vries
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands
| | - Ang Li
- Department of Applied Physics, Eindhoven University of Technology, Postbox 513, 5600 MB, Eindhoven, The Netherlands
| | - Erik P A M Bakkers
- QuTech and Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA, Delft, The Netherlands
- Department of Applied Physics, Eindhoven University of Technology, Postbox 513, 5600 MB, Eindhoven, The Netherlands
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| | - Floris A Zwanenburg
- MESA+ Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE, Enschede, The Netherlands
| |
Collapse
|
14
|
Watzinger H, Kukučka J, Vukušić L, Gao F, Wang T, Schäffler F, Zhang JJ, Katsaros G. A germanium hole spin qubit. Nat Commun 2018; 9:3902. [PMID: 30254225 PMCID: PMC6156604 DOI: 10.1038/s41467-018-06418-4] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/28/2018] [Indexed: 11/09/2022] Open
Abstract
Holes confined in quantum dots have gained considerable interest in the past few years due to their potential as spin qubits. Here we demonstrate two-axis control of a spin 3/2 qubit in natural Ge. The qubit is formed in a hut wire double quantum dot device. The Pauli spin blockade principle allowed us to demonstrate electric dipole spin resonance by applying a radio frequency electric field to one of the electrodes defining the double quantum dot. Coherent hole spin oscillations with Rabi frequencies reaching 140 MHz are demonstrated and dephasing times of 130 ns are measured. The reported results emphasize the potential of Ge as a platform for fast and electrically tunable hole spin qubit devices.
Collapse
Affiliation(s)
- Hannes Watzinger
- Institute of Science and Technology Austria, Am Campus 1, 3400, Klosterneuburg, Austria.
| | - Josip Kukučka
- Institute of Science and Technology Austria, Am Campus 1, 3400, Klosterneuburg, Austria.
| | - Lada Vukušić
- Institute of Science and Technology Austria, Am Campus 1, 3400, Klosterneuburg, Austria
| | - Fei Gao
- National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Ting Wang
- National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
| | - Friedrich Schäffler
- Johannes Kepler University, Institute of Semiconductor and Solid State Physics, Altenbergerstr, 69, 4040, Linz, Austria
| | - Jian-Jun Zhang
- National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences, 100190, Beijing, China
- CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, 100190, Beijing, China
| | - Georgios Katsaros
- Institute of Science and Technology Austria, Am Campus 1, 3400, Klosterneuburg, Austria
| |
Collapse
|
15
|
Bogan A, Studenikin S, Korkusinski M, Gaudreau L, Zawadzki P, Sachrajda AS, Tracy L, Reno J, Hargett T. Landau-Zener-Stückelberg-Majorana Interferometry of a Single Hole. PHYSICAL REVIEW LETTERS 2018; 120:207701. [PMID: 29864336 DOI: 10.1103/physrevlett.120.207701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Indexed: 06/08/2023]
Abstract
We perform Landau-Zener-Stückelberg-Majorana (LZSM) spectroscopy on a system with strong spin-orbit interaction (SOI), realized as a single hole confined in a gated double quantum dot. Analogous to electron systems, at a magnetic field B=0 and high modulation frequencies, we observe photon-assisted tunneling between dots, which smoothly evolves into the typical LZSM funnel-shaped interference pattern as the frequency is decreased. In contrast to electrons, the SOI enables an additional, efficient spin-flip interdot tunneling channel, introducing a distinct interference pattern at finite B. Magnetotransport spectra at low-frequency LZSM driving show the two channels to be equally coherent. High-frequency LZSM driving reveals complex photon-assisted tunneling pathways, both spin conserving and spin flip, which form closed loops at critical magnetic fields. In one such loop, an arbitrary hole spin state is inverted, opening the way toward its all-electrical manipulation.
Collapse
Affiliation(s)
- Alex Bogan
- Emerging Technology Division, National Research Council, Ottawa, Canada K1A0R6
| | - Sergei Studenikin
- Emerging Technology Division, National Research Council, Ottawa, Canada K1A0R6
| | - Marek Korkusinski
- Emerging Technology Division, National Research Council, Ottawa, Canada K1A0R6
| | - Louis Gaudreau
- Emerging Technology Division, National Research Council, Ottawa, Canada K1A0R6
| | - Piotr Zawadzki
- Emerging Technology Division, National Research Council, Ottawa, Canada K1A0R6
| | - Andy S Sachrajda
- Emerging Technology Division, National Research Council, Ottawa, Canada K1A0R6
| | - Lisa Tracy
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - John Reno
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - Terry Hargett
- Center for Integrated Nanotechnologies, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| |
Collapse
|
16
|
Shiri D, Verma A, Nekovei R, Isacsson A, Selvakumar CR, Anantram MP. Gunn-Hilsum Effect in Mechanically Strained Silicon Nanowires: Tunable Negative Differential Resistance. Sci Rep 2018; 8:6273. [PMID: 29674663 PMCID: PMC5908846 DOI: 10.1038/s41598-018-24387-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 03/21/2018] [Indexed: 11/09/2022] Open
Abstract
Gunn (or Gunn-Hilsum) Effect and its associated negative differential resistivity (NDR) emanates from transfer of electrons between two different energy subbands. This effect was observed in semiconductors like GaAs which has a direct bandgap of very low effective mass and an indirect subband of high effective mass which lies ~300 meV above the former. In contrast to GaAs, bulk silicon has a very high energy spacing (~1 eV) which renders the initiation of transfer-induced NDR unobservable. Using Density Functional Theory (DFT), semi-empirical 10 orbital (sp3d5s*) Tight Binding and Ensemble Monte Carlo (EMC) methods we show for the first time that (a) Gunn Effect can be induced in silicon nanowires (SiNW) with diameters of 3.1 nm under +3% strain and an electric field of 5000 V/cm, (b) the onset of NDR in the I-V characteristics is reversibly adjustable by strain and (c) strain modulates the resistivity by a factor 2.3 for SiNWs of normal I-V characteristics i.e. those without NDR. These observations are promising for applications of SiNWs in electromechanical sensors and adjustable microwave oscillators. It is noteworthy that the observed NDC is different in principle from Esaki-Diode and Resonant Tunneling Diodes (RTD) in which NDR originates from tunneling effect.
Collapse
Affiliation(s)
- Daryoush Shiri
- Department of Physics, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
| | - Amit Verma
- Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas, 78363, USA
| | - Reza Nekovei
- Department of Electrical Engineering and Computer Science, Texas A&M University-Kingsville, Kingsville, Texas, 78363, USA
| | - Andreas Isacsson
- Department of Physics, Chalmers University of Technology, SE-41296, Göteborg, Sweden
| | - C R Selvakumar
- Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
| | - M P Anantram
- Department of Electrical Engineering, University of Washington, Seattle, Washington, 98195-2500, USA
| |
Collapse
|
17
|
Li Y, Li SX, Gao F, Li HO, Xu G, Wang K, Liu D, Cao G, Xiao M, Wang T, Zhang JJ, Guo GC, Guo GP. Coupling a Germanium Hut Wire Hole Quantum Dot to a Superconducting Microwave Resonator. NANO LETTERS 2018; 18:2091-2097. [PMID: 29468882 DOI: 10.1021/acs.nanolett.8b00272] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Realizing a strong coupling between spin and resonator is an important issue for scalable quantum computation in semiconductor systems. Benefiting from the advantages of a strong spin-orbit coupling strength and long coherence time, the Ge hut wire, which is proposed to be site-controlled grown for scalability, is considered to be a promising candidate to achieve this goal. Here we present a hybrid architecture in which an on-chip superconducting microwave resonator is coupled to the holes in a Ge quantum dot. The charge stability diagram can be obtained from the amplitude and phase responses of the resonator independently from the DC transport measurement. Furthermore, we estimate the hole-resonator coupling rate of gc/2π = 148 MHz in the single quantum dot-resonator system and estimate the spin-resonator coupling rate gs/2π to be in the range 2-4 MHz. We anticipate that strong coupling between hole spins and microwave photons in a Ge hut wire is feasible with optimized schemes in the future.
Collapse
Affiliation(s)
- Yan Li
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Shu-Xiao Li
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Fei Gao
- National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Science, University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Hai-Ou Li
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Gang Xu
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Ke Wang
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Di Liu
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Gang Cao
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Ming Xiao
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Ting Wang
- National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Science, University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Jian-Jun Zhang
- National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences , Beijing 100190 , China
- School of Physical Science, University of Chinese Academy of Sciences , Beijing 100190 , China
| | - Guang-Can Guo
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| | - Guo-Ping Guo
- Key Laboratory of Quantum Information, CAS , University of Science and Technology of China , Hefei , Anhui 230026 , China
- Synergetic Innovation Center of Quantum Information & Quantum Physics , University of Science and Technology of China , Hefei , Anhui 230026 , China
| |
Collapse
|
18
|
Luo JW, Li SS, Zunger A. Rapid Transition of the Hole Rashba Effect from Strong Field Dependence to Saturation in Semiconductor Nanowires. PHYSICAL REVIEW LETTERS 2017; 119:126401. [PMID: 29341631 DOI: 10.1103/physrevlett.119.126401] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Indexed: 06/07/2023]
Abstract
The electric field manipulation of the Rashba spin-orbit coupling effects provides a route to electrically control spins, constituting the foundation of the field of semiconductor spintronics. In general, the strength of the Rashba effects depends linearly on the applied electric field and is significant only for heavy-atom materials with large intrinsic spin-orbit interaction under high electric fields. Here, we illustrate in 1D semiconductor nanowires an anomalous field dependence of the hole (but not electron) Rashba effect (HRE). (i) At low fields, the strength of the HRE exhibits a steep increase with the field so that even low fields can be used for device switching. (ii) At higher fields, the HRE undergoes a rapid transition to saturation with a giant strength even for light-atom materials such as Si (exceeding 100 meV Å). (iii) The nanowire-size dependence of the saturation HRE is rather weak for light-atom Si, so size fluctuations would have a limited effect; this is a key requirement for scalability of Rashba-field-based spintronic devices. These three features offer Si nanowires as a promising platform for the realization of scalable complementary metal-oxide-semiconductor compatible spintronic devices.
Collapse
Affiliation(s)
- Jun-Wei Luo
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Shu-Shen Li
- State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China
- College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing 100049, China
- Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Alex Zunger
- Renewable and Sustainable Energy Institute, University of Colorado, Boulder, Colorado 80309, USA
| |
Collapse
|
19
|
Jaishi M, Pati R. Catching the electron in action in real space inside a Ge-Si core-shell nanowire transistor. NANOSCALE 2017; 9:13425-13431. [PMID: 28880035 DOI: 10.1039/c7nr05589g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Catching the electron in action in real space inside a semiconductor Ge-Si core-shell nanowire field effect transistor (FET), which has been demonstrated (J. Xiang, W. Lu, Y. Hu, Y. Wu, H. Yan and C. M. Lieber, Nature, 2006, 441, 489) to outperform the state-of-the-art metal oxide semiconductor FET, is central to gaining unfathomable access into the origin of its functionality. Here, using a quantum transport approach that does not make any assumptions on electronic structure, charge, and potential profile of the device, we unravel the most probable tunneling pathway for electrons in a Ge-Si core-shell nanowire FET with orbital level spatial resolution, which demonstrates gate bias induced decoupling of electron transport between the core and the shell region. Our calculation yields excellent transistor characteristics as noticed in the experiment. Upon increasing the gate bias beyond a threshold value, we observe a rapid drop in drain current resulting in a gate bias driven negative differential resistance behavior and switching in the sign of trans-conductance. We attribute this anomalous behavior in drain current to the gate bias induced modification of the carrier transport pathway from the Ge core to the Si shell region of the nanowire channel. A new experiment involving a four probe junction is proposed to confirm our prediction on gate bias induced decoupling.
Collapse
Affiliation(s)
- Meghnath Jaishi
- Department of Physics, Michigan Technological University, Houghton, MI 49931, USA.
| | | |
Collapse
|
20
|
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: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [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.
Collapse
Affiliation(s)
- D Kotekar-Patil
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, United States of America
| | | | | | | | | |
Collapse
|
21
|
Vukušić L, Kukučka J, Watzinger H, Katsaros G. Fast Hole Tunneling Times in Germanium Hut Wires Probed by Single-Shot Reflectometry. NANO LETTERS 2017; 17:5706-5710. [PMID: 28795821 PMCID: PMC5599875 DOI: 10.1021/acs.nanolett.7b02627] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 08/09/2017] [Indexed: 06/07/2023]
Abstract
Heavy holes confined in quantum dots are predicted to be promising candidates for the realization of spin qubits with long coherence times. Here we focus on such heavy-hole states confined in germanium hut wires. By tuning the growth density of the latter we can realize a T-like structure between two neighboring wires. Such a structure allows the realization of a charge sensor, which is electrostatically and tunnel coupled to a quantum dot, with charge-transfer signals as high as 0.3 e. By integrating the T-like structure into a radiofrequency reflectometry setup, single-shot measurements allowing the extraction of hole tunneling times are performed. The extracted tunneling times of less than 10 μs are attributed to the small effective mass of Ge heavy-hole states and pave the way toward projective spin readout measurements.
Collapse
Affiliation(s)
- Lada Vukušić
- Institute
of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Josip Kukučka
- Institute
of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Hannes Watzinger
- Institute
of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
| | - Georgios Katsaros
- Institute
of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Johannes
Kepler University, Institute of Semiconductor
and Solid State Physics, Altenbergerstr. 69, 4040 Linz, Austria
| |
Collapse
|
22
|
Koelling S, Li A, Cavalli A, Assali S, Car D, Gazibegovic S, Bakkers EPAM, Koenraad PM. Atom-by-Atom Analysis of Semiconductor Nanowires with Parts Per Million Sensitivity. NANO LETTERS 2017; 17:599-605. [PMID: 28002677 DOI: 10.1021/acs.nanolett.6b03109] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The functionality of semiconductor devices is determined by the incorporation of dopants at concentrations down to the parts per million (ppm) level and below. Optimization of intentional and unintentional impurity doping relies on methods to detect and map the level of impurities. Detecting such low concentrations of impurities in nanostructures is however challenging to date as on the one hand methods used for macroscopic samples cannot be applied due to the inherent small volumes or faceted surfaces and on the other hand conventional microscopic analysis techniques are not sufficiently sensitive. Here, we show that we can detect and map impurities at the ppm level in semiconductor nanowires using atom probe tomography. We develop a method applicable to a wide variety of nanowires relevant for electronic and optical devices. We expect that it will contribute significantly to the further optimization of the synthesis of nanowires, nanostructures and devices based on these structures.
Collapse
Affiliation(s)
- S Koelling
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
| | - A Li
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
- Key Lab of Microstructure and Property of Advanced Materials, Beijing University of Technology , Beijing, 100024, China
| | - A Cavalli
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
| | - S Assali
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
| | - D Car
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
- Quantum Transport Group, Kavli Institute , Delft, 2628 CJ, The Netherlands
| | - S Gazibegovic
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
- Quantum Transport Group, Kavli Institute , Delft, 2628 CJ, The Netherlands
| | - E P A M Bakkers
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
- Quantum Transport Group, Kavli Institute , Delft, 2628 CJ, The Netherlands
| | - P M Koenraad
- Photonics and Semiconductor Nanophysics, Eindhoven University of Technology , Eindhoven, 5600 MB, The Netherlands
| |
Collapse
|
23
|
Wang DQ, Klochan O, Hung JT, Culcer D, Farrer I, Ritchie DA, Hamilton AR. Anisotropic Pauli Spin Blockade of Holes in a GaAs Double Quantum Dot. NANO LETTERS 2016; 16:7685-7689. [PMID: 27960447 DOI: 10.1021/acs.nanolett.6b03752] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Electrically defined semiconductor quantum dots are attractive systems for spin manipulation and quantum information processing. Heavy-holes in both Si and GaAs are promising candidates for all-electrical spin manipulation, owing to the weak hyperfine interaction and strong spin-orbit interaction. However, it has only recently become possible to make stable quantum dots in these systems, mainly due to difficulties in device fabrication and stability. Here, we present electrical transport measurements on holes in a gate-defined double quantum dot in a GaAs/AlxGa1-xAs heterostructure. We observe clear Pauli spin blockade and demonstrate that the lifting of this spin blockade by an external magnetic field is highly anisotropic. Numerical calculations of heavy-hole transport through a double quantum dot in the presence of strong spin-orbit coupling show quantitative agreement with experimental results and suggest that the observed anisotropy can be explained by both the anisotropic effective hole g-factor and the surface Dresselhaus spin-orbit interaction.
Collapse
Affiliation(s)
- Daisy Q Wang
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
| | - Oleh Klochan
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
| | - Jo-Tzu Hung
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
| | - Dimitrie Culcer
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
| | - Ian Farrer
- Cavendish Laboratory, J. J. Thomson Avenue , Cambridge CB3 0HE, United Kingdom
| | - David A Ritchie
- Cavendish Laboratory, J. J. Thomson Avenue , Cambridge CB3 0HE, United Kingdom
| | - Alex R Hamilton
- School of Physics, University of New South Wales, Sydney NSW 2052, Australia
| |
Collapse
|
24
|
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] [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.
Collapse
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
| |
Collapse
|
25
|
Watzinger H, Kloeffel C, Vukušić L, Rossell MD, Sessi V, Kukučka J, Kirchschlager R, Lausecker E, Truhlar A, Glaser M, Rastelli A, Fuhrer A, Loss D, Katsaros G. Heavy-Hole States in Germanium Hut Wires. NANO LETTERS 2016; 16:6879-6885. [PMID: 27656760 PMCID: PMC5108027 DOI: 10.1021/acs.nanolett.6b02715] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 09/12/2016] [Indexed: 05/14/2023]
Abstract
Hole spins have gained considerable interest in the past few years due to their potential for fast electrically controlled qubits. Here, we study holes confined in Ge hut wires, a so-far unexplored type of nanostructure. Low-temperature magnetotransport measurements reveal a large anisotropy between the in-plane and out-of-plane g-factors of up to 18. Numerical simulations verify that this large anisotropy originates from a confined wave function of heavy-hole character. A light-hole admixture of less than 1% is estimated for the states of lowest energy, leading to a surprisingly large reduction of the out-of-plane g-factors compared with those for pure heavy holes. Given this tiny light-hole contribution, the spin lifetimes are expected to be very long, even in isotopically nonpurified samples.
Collapse
Affiliation(s)
- Hannes Watzinger
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Christoph Kloeffel
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Lada Vukušić
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Marta D. Rossell
- Electron Microscopy
Center, Empa, Swiss Federal Laboratories for Materials Science and
Technology, Überlandstrasse
129, 8600 Dübendorf, Switzerland
- IBM Research Zürich, CH-8803 Rüschlikon, Switzerland
| | - Violetta Sessi
- Chair for Nanoelectronic Materials, Technical University Dresden, 01062 Dresden, Germany
| | - Josip Kukučka
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Raimund Kirchschlager
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Elisabeth Lausecker
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Alisha Truhlar
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Martin Glaser
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | - Armando Rastelli
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| | | | - Daniel Loss
- Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel, Switzerland
| | - Georgios Katsaros
- Institute of Science and Technology Austria, Am Campus 1, 3400 Klosterneuburg, Austria
- Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, 4040 Linz, Austria
| |
Collapse
|
26
|
Liu B, Yang B, Yuan F, Liu Q, Shi D, Jiang C, Zhang J, Staedler T, Jiang X. Defect-Induced Nucleation and Epitaxy: A New Strategy toward the Rational Synthesis of WZ-GaN/3C-SiC Core-Shell Heterostructures. NANO LETTERS 2015; 15:7837-7846. [PMID: 26517395 DOI: 10.1021/acs.nanolett.5b02454] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this work, we demonstrate a new strategy to create WZ-GaN/3C-SiC heterostructure nanowires, which feature controllable morphologies. The latter is realized by exploiting the stacking faults in 3C-SiC as preferential nucleation sites for the growth of WZ-GaN. Initially, cubic SiC nanowires with an average diameter of ∼100 nm, which display periodic stacking fault sections, are synthesized in a chemical vapor deposition (CVD) process to serve as the core of the heterostructure. Subsequently, hexagonal wurtzite-type GaN shells with different shapes are grown on the surface of 3C-SiC wire core. In this context, it is possible to obtain two types of WZ-GaN/3C-SiC heterostructure nanowires by means of carefully controlling the corresponding CVD reactions. Here, the stacking faults, initially formed in 3C-SiC nanowires, play a key role in guiding the epitaxial growth of WZ-GaN as they represent surface areas of the 3C-SiC nanowires that feature a higher surface energy. A dedicated structural analysis of the interfacial region by means of high-resolution transmission electron microscopy (HRTEM) revealed that the disordering of the atom arrangements in the SiC defect area promotes a lattice-matching with respect to the WZ-GaN phase, which results in a preferential nucleation. All WZ-GaN crystal domains exhibit an epitaxial growth on 3C-SiC featuring a crystallographic relationship of [12̅10](WZ-GaN) //[011̅](3C-SiC), (0001)(WZ-GaN)//(111)(3C-SiC), and d(WZ-GaN(0001)) ≈ 2d(3C-SiC(111)). The approach to utilize structural defects of a nanowire core to induce a preferential nucleation of foreign shells generally opens up a number of opportunities for the epitaxial growth of a wide range of semiconductor nanostructures which are otherwise impossible to acquire. Consequently, this concept possesses tremendous potential for the applications of semiconductor heterostructures in various fields such as optics, electrics, electronics, and photocatalysis for energy harvesting and environment processing.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Thorsten Staedler
- Institute of Materials Engineering, University of Siegen, Germany , Paul-Bonatz-Strasse 9-11, 57076 Siegen, Germany
| | - Xin Jiang
- Institute of Materials Engineering, University of Siegen, Germany , Paul-Bonatz-Strasse 9-11, 57076 Siegen, Germany
| |
Collapse
|
27
|
Li R, Hudson FE, Dzurak AS, Hamilton AR. Pauli Spin Blockade of Heavy Holes in a Silicon Double Quantum Dot. NANO LETTERS 2015; 15:7314-8. [PMID: 26434407 DOI: 10.1021/acs.nanolett.5b02561] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
In this work, we study hole transport in a planar silicon metal-oxide-semiconductor based double quantum dot. We demonstrate Pauli spin blockade in the few hole regime and map the spin relaxation induced leakage current as a function of interdot level spacing and magnetic field. With varied interdot tunnel coupling, we can identify different dominant spin relaxation mechanisms. Application of a strong out-of-plane magnetic field causes an avoided singlet-triplet level crossing, from which the heavy hole g-factor ~0.93 and the strength of spin-orbit interaction ~110 μeV can be obtained. The demonstrated strong spin-orbit interaction of heavy holes promises fast local spin manipulation using only electric fields, which is of great interest for quantum information processing.
Collapse
Affiliation(s)
- Ruoyu Li
- School of Physics, ‡Australian National Fabrication Facility, and §Centre of Excellence for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Fay E Hudson
- School of Physics, ‡Australian National Fabrication Facility, and §Centre of Excellence for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Andrew S Dzurak
- School of Physics, ‡Australian National Fabrication Facility, and §Centre of Excellence for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales , Sydney, New South Wales 2052, Australia
| | - Alexander R Hamilton
- School of Physics, ‡Australian National Fabrication Facility, and §Centre of Excellence for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales , Sydney, New South Wales 2052, Australia
| |
Collapse
|
28
|
Opoku C, Dahiya AS, Oshman C, Daumont C, Cayrel F, Poulin-Vittrant G, Alquier D, Camara N. Fabrication of high performance field-effect transistors and practical Schottky contacts using hydrothermal ZnO nanowires. NANOTECHNOLOGY 2015; 26:355704. [PMID: 26245930 DOI: 10.1088/0957-4484/26/35/355704] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The production of large quantities of single crystalline semiconducting ZnO nanowires (NWs) at low cost can offer practical solutions to realizing several novel electronic/optoelectronic and sensor applications on an industrial scale. The present work demonstrates high-density single crystalline NWs synthesized by a multiple cycle hydrothermal process at ∼100 °C. The high carrier concentration in such ZnO NWs is greatly suppressed by a simple low cost thermal annealing step in ambient air at ∼450 °C. Single ZnO NW FETs incorporating these modified NWs are characterized, revealing strong metal work function-dependent charge transport, unobtainable with as-grown hydrothermal ZnO NWs. Single ZnO NW FETs with Al as source and drain (s/d) contacts show excellent performance metrics, including low off-state currents (fA range), high on/off ratio (10(5)-10(7)), steep subthreshold slope (<600 mV/dec) and excellent field-effect carrier mobility (5-11 cm(2)/V-s). Modified ZnO NWs with platinum s/d contacts demonstrate excellent Schottky transport characteristics, markedly different from a reference ZnO NW device with Al contacts. This included abrupt reverse bias current-voltage saturation characteristics and positive temperature coefficient (∼0.18 eV to 0.13 eV). This work is envisaged to benefit many areas of hydrothermal ZnO NW research, such as NW FETs, piezoelectric energy recovery, piezotronics and Schottky diodes.
Collapse
Affiliation(s)
- Charles Opoku
- Université François Rabelais de Tours, CNRS, GREMAN UMR 7347, 16 rue Pierre et Marie Curie, 37071 TOURS Cedex2, France
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Guo Q, Zhang M, Xue Z, Wang G, Chen D, Cao R, Huang G, Mei Y, Di Z, Wang X. Deterministic Assembly of Flexible Si/Ge Nanoribbons via Edge-Cutting Transfer and Printing for van der Waals Heterojunctions. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2015; 11:4140-4148. [PMID: 25966037 DOI: 10.1002/smll.201500505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 04/23/2015] [Indexed: 06/04/2023]
Abstract
As the promising building blocks for flexible electronics and photonics, inorganic semiconductor nanomembranes have attracted considerable attention owing to their excellent mechanical flexibility and electrical/optical properties. To functionalize these building blocks with complex components, transfer and printing methods in a convenient and precise way are urgently demanded. A combined and controllable approach called edge-cutting transfer method to assemble semiconductor nanoribbons with defined width (down to submicrometer) and length (up to millimeter) is proposed. The transfer efficiency can be comprehended by a classical cantilever model, in which the difference of stress distributions between forth and back edges is investigated using finite element method. In addition, the vertical van der Waals PN (p-Si/n-Ge) junction constructed by a two-round process presents a typical rectifying behavior. The proposed technology may provide a practical, reliable, and cost-efficient strategy for transfer and printing routines, and thus expediting its potential applications for roll-to-roll productions for flexible devices.
Collapse
Affiliation(s)
- Qinglei Guo
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Miao Zhang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Zhongying Xue
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Gang Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Da Chen
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Ronggen Cao
- Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Gaoshan Huang
- Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Yongfeng Mei
- Department of Materials Science, Fudan University, Shanghai, 200433, P. R. China
| | - Zengfeng Di
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| | - Xi Wang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, P. R. China
| |
Collapse
|
30
|
Tan TL, Ng MF. Computational screening for effective Ge1−xSix nanowire photocatalyst. Phys Chem Chem Phys 2015; 17:20391-7. [PMID: 26194782 DOI: 10.1039/c5cp03077c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Band edges of GeSi core–shell structures versus the size and the composition compared to various redox reaction potentials for water-splitting reaction.
Collapse
Affiliation(s)
- Teck L. Tan
- Institute of High Performance Computing
- Agency for Science
- Technology and Research
- Singapore 138632
- Singapore
| | - Man-Fai Ng
- Institute of High Performance Computing
- Agency for Science
- Technology and Research
- Singapore 138632
- Singapore
| |
Collapse
|
31
|
Kawakami E, Scarlino P, Ward DR, Braakman FR, Savage DE, Lagally MG, Friesen M, Coppersmith SN, Eriksson MA, Vandersypen LMK. Electrical control of a long-lived spin qubit in a Si/SiGe quantum dot. NATURE NANOTECHNOLOGY 2014; 9:666-670. [PMID: 25108810 DOI: 10.1038/nnano.2014.153] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 06/27/2014] [Indexed: 06/03/2023]
Abstract
Nanofabricated quantum bits permit large-scale integration but usually suffer from short coherence times due to interactions with their solid-state environment. The outstanding challenge is to engineer the environment so that it minimally affects the qubit, but still allows qubit control and scalability. Here, we demonstrate a long-lived single-electron spin qubit in a Si/SiGe quantum dot with all-electrical two-axis control. The spin is driven by resonant microwave electric fields in a transverse magnetic field gradient from a local micromagnet, and the spin state is read out in the single-shot mode. Electron spin resonance occurs at two closely spaced frequencies, which we attribute to two valley states. Thanks to the weak hyperfine coupling in silicon, a Ramsey decay timescale of 1 μs is observed, almost two orders of magnitude longer than the intrinsic timescales in GaAs quantum dots, whereas gate operation times are comparable to those reported in GaAs. The spin echo decay time is ~40 μs, both with one and four echo pulses, possibly limited by intervalley scattering. These advances strongly improve the prospects for quantum information processing based on quantum dots.
Collapse
Affiliation(s)
- E Kawakami
- 1] Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands [2]
| | - P Scarlino
- 1] Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands [2]
| | - D R Ward
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - F R Braakman
- 1] Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands [2]
| | - D E Savage
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M G Lagally
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Mark Friesen
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - S N Coppersmith
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M A Eriksson
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L M K Vandersypen
- Kavli Institute of Nanoscience, TU Delft, Lorentzweg 1, 2628 CJ Delft, The Netherlands
| |
Collapse
|