1
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Kessing RK, Yang PY, Manmana SR, Cao J. Long-Range Nonequilibrium Coherent Tunneling Induced by Fractional Vibronic Resonances. J Phys Chem Lett 2022; 13:6831-6838. [PMID: 35857895 DOI: 10.1021/acs.jpclett.2c01455] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We study the influence of a linear energy bias on a nonequilibrium excitation on a chain of molecules coupled to local vibrations (a tilted Holstein model) using both a random-walk rate kernel theory and a nonperturbative, massively parallelized adaptive-basis algorithm. We uncover structured and discrete vibronic resonance behavior fundamentally different from both linear response theory and homogeneous polaron dynamics. Remarkably, resonance between the phonon energy ℏω and the bias δϵ occurs not only at integer but also fractional ratios δϵ/(ℏω) = m/n, which effect long-range n-bond m-phonon tunneling. These observations are reproduced in a model calculation of a recently demonstrated Cy3 system, and the effect of dipole-dipole-type non-nearest-neighbor coupling and vibrationally relaxed initial states is also considered. Potential applications range from molecular electronics to optical lattices and artificial light harvesting via vibronic engineering of coherent quantum transport.
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Affiliation(s)
- R Kevin Kessing
- Institut für Theoretische Physik, Universität Ulm, Ulm, 89069, Germany
- Institut für Theoretische Physik, Georg-August-Universität Göttingen, Göttingen, 37077, Germany
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Pei-Yun Yang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
- Department of Physics, National Taiwan University, Taipei, 10617, Taiwan (R.O.C.)
- Beijing Computational Science Research Center, Beijing, 100193, China
| | - Salvatore R Manmana
- Institut für Theoretische Physik, Georg-August-Universität Göttingen, Göttingen, 37077, Germany
- Fachbereich Physik, Philipps-Universität Marburg, Marburg, 35032, Germany
| | - Jianshu Cao
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
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2
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Dorsch S, Svilans A, Josefsson M, Goldozian B, Kumar M, Thelander C, Wacker A, Burke A. Heat Driven Transport in Serial Double Quantum Dot Devices. NANO LETTERS 2021; 21:988-994. [PMID: 33459021 PMCID: PMC7875509 DOI: 10.1021/acs.nanolett.0c04017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/12/2021] [Indexed: 06/12/2023]
Abstract
Studies of thermally induced transport in nanostructures provide access to an exciting regime where fluctuations are relevant, enabling the investigation of fundamental thermodynamic concepts and the realization of thermal energy harvesters. We study a serial double quantum dot formed in an InAs/InP nanowire coupled to two electron reservoirs. By means of a specially designed local metallic joule-heater, the temperature of the phonon bath in the vicinity of the double quantum dot can be enhanced. This results in phonon-assisted transport, enabling the conversion of local heat into electrical power in a nanosized heat engine. Simultaneously, the electron temperatures of the reservoirs are affected, resulting in conventional thermoelectric transport. By detailed modeling and experimentally tuning the interdot coupling, we disentangle both effects. Furthermore, we show that phonon-assisted transport is sensitive to excited states. Our findings demonstrate the versatility of our design to study fluctuations and fundamental nanothermodynamics.
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Affiliation(s)
- Sven Dorsch
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Artis Svilans
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Martin Josefsson
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Bahareh Goldozian
- Mathematical
Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Mukesh Kumar
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Claes Thelander
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Andreas Wacker
- Mathematical
Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
| | - Adam Burke
- Solid
State Physics and NanoLund, Lund University, Box 118, SE-221 00 Lund, Sweden
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3
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Chen L, Skibitzki O, Pedesseau L, Létoublon A, Stervinou J, Bernard R, Levallois C, Piron R, Perrin M, Schubert MA, Moréac A, Durand O, Schroeder T, Bertru N, Even J, Léger Y, Cornet C. Strong Electron-Phonon Interaction in 2D Vertical Homovalent III-V Singularities. ACS NANO 2020; 14:13127-13136. [PMID: 32960037 DOI: 10.1021/acsnano.0c04702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Highly polar materials are usually preferred over weakly polar ones to study strong electron-phonon interactions and its fascinating properties. Here, we report on the achievement of simultaneous confinement of charge carriers and phonons at the vicinity of a 2D vertical homovalent singularity (antiphase boundary, APB) in an (In,Ga)P/SiGe/Si sample. The impact of the electron-phonon interaction on the photoluminescence processes is then clarified by combining transmission electron microscopy, X-ray diffraction, ab initio calculations, Raman spectroscopy, and photoluminescence experiments. 2D localization and layer group symmetry properties of homovalent electronic states and phonons are studied by first-principles methods, leading to the prediction of a type-II band alignment between the APB and the surrounding semiconductor matrix. A Huang-Rhys factor of 8 is finally experimentally determined for the APB emission line, underlining that a large and unusually strong electron-phonon coupling can be achieved by 2D vertical quantum confinement in an undoped III-V semiconductor. This work extends the concept of an electron-phonon interaction to 2D vertically buried III-V homovalent nano-objects and therefore provides different approaches for material designs, vertical carrier transport, heterostructure design on silicon, and device applications with weakly polar semiconductors.
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Affiliation(s)
- Lipin Chen
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Oliver Skibitzki
- IHP-Leibniz Institut fuer Innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Laurent Pedesseau
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Antoine Létoublon
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Julie Stervinou
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Rozenn Bernard
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | | | - Rozenn Piron
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Mathieu Perrin
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Markus Andreas Schubert
- IHP-Leibniz Institut fuer Innovative Mikroelektronik, Im Technologiepark 25, 15236 Frankfurt (Oder), Germany
| | - Alain Moréac
- Univ Rennes, CNRS, IPR (Institut de Physique de Rennes)-UMR 6251, 35000 Rennes, France
| | - Olivier Durand
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Thomas Schroeder
- Leibniz-Institut für Kristallzüchtung (IKZ), 12489 Berlin, Germany
| | - Nicolas Bertru
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Jacky Even
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Yoan Léger
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
| | - Charles Cornet
- Univ Rennes, INSA Rennes, CNRS, Institut FOTON-UMR 6082, F-35000 Rennes, France
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4
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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.
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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
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5
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Wang Z, Yuan Y, Liu X, Sun J, Muruganathan M, Mizuta H. Quantum Dot Formation in Controllably Doped Graphene Nanoribbon. ACS NANO 2019; 13:7502-7507. [PMID: 31150193 DOI: 10.1021/acsnano.9b02935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We introduce the controllable doping from hydrogen silsesquioxane (HSQ) to graphene by changing its electron-beam exposure dose. Using HSQ as the dopant, a fine-resolution electron-beam resist allows us to selectively dope graphene with an extremely high spatial resolution of a few nanometers. Therefore, we can design and demonstrate the single quantum dot (QD)-like transport in the graphene nanoribbon (GNR) with the opening of the energy gap. Moreover, we suggest a rough geometric design rule in which a relatively short and wide GNR is required for observing the single QD-like transport. We envisage that this method can be utilized for other materials and for other applications, such as p-n junctions and tunnel field-effect transistors.
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Affiliation(s)
- Zhongwang Wang
- School of Materials Science , Japan Advanced Institute of Science and Technology , 1-1 Asahidai , Nomi , Ishikawa 923-1292 , Japan
| | | | | | | | - Manoharan Muruganathan
- School of Materials Science , Japan Advanced Institute of Science and Technology , 1-1 Asahidai , Nomi , Ishikawa 923-1292 , Japan
| | - Hiroshi Mizuta
- School of Materials Science , Japan Advanced Institute of Science and Technology , 1-1 Asahidai , Nomi , Ishikawa 923-1292 , Japan
- Hitachi Cambridge Laboratory , Hitachi Europe Ltd. , J. J. Thomson Avenue , CB3 0HE Cambridge , United Kingdom
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6
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Datta D, Krishnababu K, Stroscio MA, Dutta M. Effect of quantum confinement on lifetime of anharmonic decay of optical phonons in semiconductor nanostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:355302. [PMID: 29972139 DOI: 10.1088/1361-648x/aad104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The anharmonic decay of phonons underlies many important effects in semiconductors, e.g. hotspot formation, phonon bottleneck and thermal resistivity. In this article, we evaluate the effect of quantum confinement on the anharmonic decay transition probability in a cubic isotropic material. This article focuses on the anharmonic decay of longitudinal optical phonons, generated from hot electrons, are directly related to formation of hotspots in the active region of semiconductor devices. The confinement effect has been realized in double interface heterostructure quantum well (DHSQW) (e.g. AlAs/GaAs/AlAs) and free-standing quantum well (FSQW) (e.g. GaAs) structures as the confined phonon modes have different properties inside the structures. The longitudinal-optical phonon decay rate is reduced for the case of a DHSQW compared to bulk material and for a FSQW the decay rate has a strong dependence on wavevector value of the three phonons involved.
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Affiliation(s)
- D Datta
- Department of Electrical and Computer Engineering, University of Illinois at Chicago, Chicago, IL, United States of America
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7
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Hartke TR, Liu YY, Gullans MJ, Petta JR. Microwave Detection of Electron-Phonon Interactions in a Cavity-Coupled Double Quantum Dot. PHYSICAL REVIEW LETTERS 2018; 120:097701. [PMID: 29547336 DOI: 10.1103/physrevlett.120.097701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Indexed: 06/08/2023]
Abstract
Quantum confinement leads to the formation of discrete electronic states in quantum dots. Here we probe electron-phonon interactions in a suspended InAs nanowire double quantum dot (DQD) that is electric-dipole coupled to a microwave cavity. We apply a finite bias across the wire to drive a steady state population in the DQD excited state, enabling a direct measurement of the electron-phonon coupling strength at the DQD transition energy. The amplitude and phase response of the cavity field exhibit oscillations that are periodic in the DQD energy level detuning due to the phonon modes of the nanowire. The observed cavity phase shift is consistent with theory that predicts a renormalization of the cavity center frequency by coupling to phonons.
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Affiliation(s)
- T R Hartke
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - Y-Y Liu
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - M J Gullans
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
| | - J R Petta
- Department of Physics, Princeton University, Princeton, New Jersey 08544, USA
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8
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Signorello G, Sant S, Bologna N, Schraff M, Drechsler U, Schmid H, Wirths S, Rossell MD, Schenk A, Riel H. Manipulating Surface States of III-V Nanowires with Uniaxial Stress. NANO LETTERS 2017; 17:2816-2824. [PMID: 28383924 DOI: 10.1021/acs.nanolett.6b05098] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
III-V compound semiconductors are indispensable materials for today's high-end electronic and optoelectronic devices and are being explored for next-generation transistor logic and quantum technologies. III-V surfaces and interfaces play the leading role in determining device performance, and therefore, methods to control their electronic properties have been developed. Typically, surface passivation studies demonstrated how to limit the density of surface states. Strain has been widely used to improve the electronic transport properties and optoelectronic properties of III-Vs, but the potential of this technology to modify the surface properties still remains to be explored. Here we show that uniaxial stress induces a shift in the energy of the surface states of III-V nanowires, modifying their electronic properties. We demonstrate this phenomenon by modulating the conductivity of InAs nanowires over 4 orders of magnitude with axial strain ranging between -2.5% in compression and 2.1% in tension. The band bending at the surface of the nanostructure is modified from accumulation to depletion reversibly and reproducibly. We provide evidence of this physical effect using a combination of electrical transport measurement, Raman spectroscopy, band-structure modeling, and technology computer aided design (TCAD) simulations. With this methodology, the deformation potentials for the surface states are quantified. These results reveal that strain technology can be used to shift surface states away from energy ranges in which device performance is negatively affected and represent a novel route to engineer the electronic properties of III-V devices.
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Affiliation(s)
- G Signorello
- IBM Research - Zurich , 8803 Rüschlikon, Switzerland
| | - S Sant
- Integrated Systems Laboratory, Department of Electrical Engineering and Information Technology, ETH Zürich , 8092 Zürich, Switzerland
| | - N Bologna
- Electron Microscopy Center, EMPA, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - M Schraff
- IBM Research - Zurich , 8803 Rüschlikon, Switzerland
| | - U Drechsler
- IBM Research - Zurich , 8803 Rüschlikon, Switzerland
| | - H Schmid
- IBM Research - Zurich , 8803 Rüschlikon, Switzerland
| | - S Wirths
- IBM Research - Zurich , 8803 Rüschlikon, Switzerland
| | - M D Rossell
- Electron Microscopy Center, EMPA, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf, Switzerland
| | - A Schenk
- Integrated Systems Laboratory, Department of Electrical Engineering and Information Technology, ETH Zürich , 8092 Zürich, Switzerland
| | - H Riel
- IBM Research - Zurich , 8803 Rüschlikon, Switzerland
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9
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Gong J, Yang M, Ma X, Schaller RD, Liu G, Kong L, Yang Y, Beard MC, Lesslie M, Dai Y, Huang B, Zhu K, Xu T. Electron-Rotor Interaction in Organic-Inorganic Lead Iodide Perovskites Discovered by Isotope Effects. J Phys Chem Lett 2016; 7:2879-87. [PMID: 27396858 DOI: 10.1021/acs.jpclett.6b01199] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We report on the carrier-rotor coupling effect in perovskite organic-inorganic hybrid lead iodide (CH3NH3PbI3) compounds discovered by isotope effects. Deuterated organic-inorganic perovskite compounds including CH3ND3PbI3, CD3NH3PbI3, and CD3ND3PbI3 were synthesized. Devices made from regular CH3NH3PbI3 and deuterated CH3ND3PbI3 exhibit comparable performance in band gap, current-voltage, carrier mobility, and power conversion efficiency. However, a time-resolved photoluminescence (TRPL) study reveals that CH3NH3PbI3 exhibits notably longer carrier lifetime than that of CH3ND3PbI3, in both thin-film and single-crystal formats. Furthermore, the comparison in carrier lifetime between CD3NH3PbI3 and CH3ND3PbI3 single crystals suggests that vibrational modes in methylammonium (MA(+)) have little impact on carrier lifetime. In contrast, the fully deuterated compound CD3ND3PbI3 reconfirmed the trend of decreasing carrier lifetime upon the increasing moment of inertia of cationic MA(+). Polaron model elucidates the electron-rotor interaction.
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Affiliation(s)
- Jue Gong
- Department of Chemistry and Biochemistry, Northern Illinois University , DeKalb, Illinois 60115, United States
| | - Mengjin Yang
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Xiangchao Ma
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan 250100, China
| | - Richard D Schaller
- Center for Nanoscale Materials, Argonne National Laboratory , Argonne, Illinois 60439, United States
| | - Gang Liu
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China
| | - Lingping Kong
- Center for High Pressure Science and Technology Advanced Research , Shanghai 201203, China
| | - Ye Yang
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Matthew C Beard
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Michael Lesslie
- Department of Chemistry and Biochemistry, Northern Illinois University , DeKalb, Illinois 60115, United States
| | - Ying Dai
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan 250100, China
| | - Baibiao Huang
- School of Physics, State Key Laboratory of Crystal Materials, Shandong University , Jinan 250100, China
| | - Kai Zhu
- Chemistry and Nanoscience Center, National Renewable Energy Laboratory , Golden, Colorado 80401, United States
| | - Tao Xu
- Department of Chemistry and Biochemistry, Northern Illinois University , DeKalb, Illinois 60115, United States
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10
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Coherent optical phonon oscillation and possible electronic softening in WTe2 crystals. Sci Rep 2016; 6:30487. [PMID: 27457385 PMCID: PMC4960623 DOI: 10.1038/srep30487] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 07/06/2016] [Indexed: 11/09/2022] Open
Abstract
A rapidly-growing interest in WTe2 has been triggered by the giant magnetoresistance effect discovered in this unique system. While many efforts have been made towards uncovering the electron- and spin-relevant mechanisms, the role of lattice vibration remains poorly understood. Here, we study the coherent vibrational dynamics in WTe2 crystals by using ultrafast pump-probe spectroscopy. The oscillation signal in time domain in WTe2 has been ascribed as due to the coherent dynamics of the lowest energy A1 optical phonons with polarization- and wavelength-dependent measurements. With increasing temperature, the phonon energy decreases due to anharmonic decay of the optical phonons into acoustic phonons. Moreover, a significant drop (15%) of the phonon energy with increasing pump power is observed which is possibly caused by the lattice anharmonicity induced by electronic excitation and phonon-phonon interaction.
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11
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Chen JCH, Sato Y, Kosaka R, Hashisaka M, Muraki K, Fujisawa T. Enhanced electron-phonon coupling for a semiconductor charge qubit in a surface phonon cavity. Sci Rep 2015; 5:15176. [PMID: 26469629 PMCID: PMC4606810 DOI: 10.1038/srep15176] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 09/18/2015] [Indexed: 11/09/2022] Open
Abstract
Electron-phonon coupling is a major decoherence mechanism, which often causes scattering and energy dissipation in semiconductor electronic systems. However, this electron-phonon coupling may be used in a positive way for reaching the strong or ultra-strong coupling regime in an acoustic version of the cavity quantum electrodynamic system. Here we propose and demonstrate a phonon cavity for surface acoustic waves, which is made of periodic metal fingers that constitute Bragg reflectors on a GaAs/AlGaAs heterostructure. Phonon band gap and cavity phonon modes are identified by frequency, time and spatially resolved measurements of the piezoelectric potential. Tunneling spectroscopy on a double quantum dot indicates the enhancement of phonon assisted transitions in a charge qubit. This encourages studying of acoustic cavity quantum electrodynamics with surface phonons.
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Affiliation(s)
- J C H Chen
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, 152-8551, Japan
| | - Y Sato
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, 152-8551, Japan
| | - R Kosaka
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, 152-8551, Japan
| | - M Hashisaka
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, 152-8551, Japan
| | - K Muraki
- NTT Basic Research Laboratories, NTT Corporation, 3-1 Morinosato-Wakamiya, Atsugi, 243-0198, Japan
| | - T Fujisawa
- Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, 152-8551, Japan
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12
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Krause T, Brandes T, Esposito M, Schaller G. Thermodynamics of the polaron master equation at finite bias. J Chem Phys 2015; 142:134106. [DOI: 10.1063/1.4916359] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Thilo Krause
- Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany
| | - Tobias Brandes
- Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany
| | - Massimiliano Esposito
- Complex Systems and Statistical Mechanics, University of Luxembourg, L-1511 Luxembourg, Luxembourg
| | - Gernot Schaller
- Institut für Theoretische Physik, Technische Universität Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany
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13
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Raman phonon emission in a driven double quantum dot. Nat Commun 2014; 5:3716. [DOI: 10.1038/ncomms4716] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 03/20/2014] [Indexed: 11/08/2022] Open
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14
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Optophononics with coupled quantum dots. Nat Commun 2014; 5:3299. [PMID: 24534815 DOI: 10.1038/ncomms4299] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 01/22/2014] [Indexed: 11/08/2022] Open
Abstract
Modern technology is founded on the intimate understanding of how to utilize and control electrons. Next to electrons, nature uses phonons, quantized vibrations of an elastic structure, to carry energy, momentum and even information through solids. Phonons permeate the crystalline components of modern technology, yet in terms of technological utilization phonons are far from being on par with electrons. Here we demonstrate how phonons can be employed to render a single quantum dot pair optically transparent. This phonon-induced transparency is realized via the formation of a molecular polaron, the result of a Fano-type quantum interference, which proves that we have accomplished making typically incoherent and dissipative phonons behave in a coherent and non-dissipative manner. We find the transparency to be widely tunable by electronic and optical means. Thereby we show amplification of weakest coupling channels. We further outline the molecular polaron's potential as a control element in phononic circuitry architecture.
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15
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Stace TM, Doherty AC, Reilly DJ. Dynamical steady States in driven quantum systems. PHYSICAL REVIEW LETTERS 2013; 111:180602. [PMID: 24237499 DOI: 10.1103/physrevlett.111.180602] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Indexed: 06/02/2023]
Abstract
We derive dynamical equations for a driven, dissipative quantum system in which the environment-induced relaxation rate is comparable to the Rabi frequency, avoiding assumptions on the frequency dependence of the environmental coupling. When the environmental coupling varies significantly on the scale of the Rabi frequency, secular or rotating wave approximations break down. We avoid these approximations, yielding dynamical steady states which account for the interaction between driven quantum dots and their phonon environment. The theory, which is motivated by recent experimental observations, qualitatively and quantitatively describes the transition from asymmetric unsaturated resonances at weak driving to population inversion at strong driving.
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Affiliation(s)
- T M Stace
- ARC Centre for Engineered Quantum Systems, University of Queensland, Brisbane 4072, Australia
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Güttinger J, Molitor F, Stampfer C, Schnez S, Jacobsen A, Dröscher S, Ihn T, Ensslin K. Transport through graphene quantum dots. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2012; 75:126502. [PMID: 23144122 DOI: 10.1088/0034-4885/75/12/126502] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
We review transport experiments on graphene quantum dots and narrow graphene constrictions. In a quantum dot, electrons are confined in all lateral dimensions, offering the possibility for detailed investigation and controlled manipulation of individual quantum systems. The recently isolated two-dimensional carbon allotrope graphene is an interesting host to study quantum phenomena, due to its novel electronic properties and the expected weak interaction of the electron spin with the material. Graphene quantum dots are fabricated by etching mono-layer flakes into small islands (diameter 60-350 nm) with narrow connections to contacts (width 20-75 nm), serving as tunneling barriers for transport spectroscopy. Electron confinement in graphene quantum dots is observed by measuring Coulomb blockade and transport through excited states, a manifestation of quantum confinement. Measurements in a magnetic field perpendicular to the sample plane allowed to identify the regime with only a few charge carriers in the dot (electron-hole transition), and the crossover to the formation of the graphene specific zero-energy Landau level at high fields. After rotation of the sample into parallel magnetic field orientation, Zeeman spin splitting with a g-factor of g ≈ 2 is measured. The filling sequence of subsequent spin states is similar to what was found in GaAs and related to the non-negligible influence of exchange interactions among the electrons.
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Affiliation(s)
- J Güttinger
- Solid State Physics Laboratory, ETH Zurich, 8092 Zurich, Switzerland.
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Sharafutdinov AU, Burmistrov IS. Cotunneling current through a two-level quantum dot coupled to magnetic leads: the role of exchange interaction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:155301. [PMID: 22436594 DOI: 10.1088/0953-8984/24/15/155301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The cotunneling current through a two-level quantum dot weakly coupled to ferromagnetic leads is studied in the Coulomb blockade regime. The cotunneling current is calculated analytically under simple but realistic assumptions as follows: (i) the quantum dot is described by the universal Hamiltonian, (ii) it is doubly occupied, and (iii) it displays a fast spin relaxation. We find that the dependence of the differential conductance on the bias voltage is significantly affected by the exchange interaction on the quantum dot. In particular, for antiparallel magnetic configurations in the leads, the exchange interaction results in the appearance of interference-type contributions from the inelastic processes to the cotunneling current. Such dependence of the cotunneling current on the tunneling amplitude phases should also occur in multi-level quantum dots weakly coupled to ferromagnetic leads near the mesoscopic Stoner instabilities.
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Taubert D, Schuh D, Wegscheider W, Ludwig S. Determination of energy scales in few-electron double quantum dots. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:123905. [PMID: 22225229 DOI: 10.1063/1.3673003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The capacitive couplings between gate-defined quantum dots and their gates vary considerably as a function of applied gate voltages. The conversion between gate voltages and the relevant energy scales is usually performed in a regime of rather symmetric dot-lead tunnel couplings strong enough to allow direct transport measurements. Unfortunately, this standard procedure fails for weak and possibly asymmetric tunnel couplings, often the case in realistic devices. We have developed methods to determine the gate voltage to energy conversion accurately in the different regimes of dot-lead tunnel couplings and demonstrate strong variations of the conversion factors. Our concepts can easily be extended to triple quantum dots or even larger arrays.
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Affiliation(s)
- D Taubert
- Center for NanoScience and Fakultät für Physik, Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, D-80539 München, Germany
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Volk C, Fringes S, Terrés B, Dauber J, Engels S, Trellenkamp S, Stampfer C. Electronic excited states in bilayer graphene double quantum dots. NANO LETTERS 2011; 11:3581-3586. [PMID: 21805985 DOI: 10.1021/nl201295s] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report tunneling spectroscopy experiments on a bilayer graphene double quantum dot device that can be tuned by all-graphene lateral gates. The diameter of the two quantum dots are around 50 nm and the constrictions acting as tunneling barriers are 30 nm in width. The double quantum dot features additional energies on the order of 20 meV. Charge stability diagrams allow us to study the tunable interdot coupling energy as well as the spectrum of the electronic excited states on a number of individual triple points over a large energy range. The obtained constant level spacing of 1.75 meV over a wide energy range is in good agreement with the expected single-particle energy spacing in bilayer graphene quantum dots. Finally, we investigate the evolution of the electronic excited states in a parallel magnetic field.
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Affiliation(s)
- C Volk
- JARA-FIT and II. Institute of Physics B, RWTH Aachen University, 52074 Aachen, Germany
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Molitor F, Güttinger J, Stampfer C, Dröscher S, Jacobsen A, Ihn T, Ensslin K. Electronic properties of graphene nanostructures. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2011; 23:243201. [PMID: 21613728 DOI: 10.1088/0953-8984/23/24/243201] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
In this review, recent developments in the fabrication and understanding of the electronic properties of graphene nanostructures are discussed. After a brief overview of the structure of graphene and the two-dimensional transport properties, the focus is put on graphene constrictions, quantum dots and double quantum dots. For constrictions with a width below 100 nm, the current through the constriction is strongly suppressed for a certain back gate voltage range, related to the so-called transport gap. This transport gap is due to the formation of localized puddles in the constriction, and its size depends strongly on the constriction width. Such constrictions can be used to confine charge carriers in quantum dots, leading to Coulomb blockade effects.
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Affiliation(s)
- F Molitor
- Solid State Physics Laboratory, ETH Zurich, Zurich, Switzerland
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