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The realization of integrated quantum circuits requires precise on-chip control of charge carriers. Aiming at the coherent coupling of distant nanostructures at zero magnetic field, here we study the ballistic electron transport through two…

Mesoscale and Nanoscale Physics · Physics 2020-09-23 Jaan Freudenfeld , Max Geier , Vladimir Umansky , Piet W. Brouwer , Stefan Ludwig

A numerically exact calculation of the T=0 transport properties of a quantum wire interacting with a lateral two-level quantum dot is presented. The wire conductance is calculated for all different states of charge and spin of the quantum…

Strongly Correlated Electrons · Physics 2007-05-23 Maria A. Davidovich , E. V. Anda , C. A. Busser , G. Chiappe

We report an electronic magnetization measurement of a quantum point contact (QPC) based on nuclear magnetic resonance (NMR) spectroscopy. We find that NMR signals can be detected by measuring the QPC conductance under in-plane magnetic…

Mesoscale and Nanoscale Physics · Physics 2015-07-16 Minoru Kawamura , Keiji Ono , Peter Stano , Kimitoshi Kono , Tomosuke Aono

A systematic theory of the conductance measurements of non-invasive (weak probe) scanning gate microscopy is presented that provides an interpretation of what precisely is being measured. A scattering approach is used to derive explicit…

Mesoscale and Nanoscale Physics · Physics 2013-07-12 C. Gorini , R. A. Jalabert , W. Szewc , S. Tomsovic , D. Weinmann

Recent theories suggest that the excitations of certain quantum Hall states may have exotic braiding statistics which could be used to build topological quantum gates. This has prompted an experimental push to study such states using…

Mesoscale and Nanoscale Physics · Physics 2015-06-25 J. B. Miller , I. P. Radu , D. M. Zumbuhl , E. M. Levenson-Falk , M. A. Kastner , C. M. Marcus , L. N. Pfeiffer , K. W. West

The metal-semiconductor contact is a major factor limiting the shrinking of transistor dimension to further increase device performance. In-plane edge contacts have the potential to achieve lower contact resistance due to stronger orbital…

Mesoscale and Nanoscale Physics · Physics 2019-02-15 Wushi Dong , Peter B. Littlewood

The temperature dependence of the conductance of a quantum point contact has been measured. The conductance as a function of the Fermi energy shows temperature-independent fixed points, located at roughly multiple integers of $e^{2}/h$.…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 V. Senz , T. Heinzel , T. Ihn , S. Lindemann , R. Held , K. Ensslin , W. Wegscheider , M. Bichler

We develop a realistic and analytically tractable model to describe the spin current which arises in a quantum point contact (QPC) with spin-orbit interaction (SOI) upon a small voltage is applied. In the model, the QPC is considered as a…

Mesoscale and Nanoscale Physics · Physics 2010-09-07 Vladimir A. Sablikov

We have calculated the admittance of a two-dimensional quantum point contact (QPC) using a novel variant of the Wigner distribution function (WDF) formalism. In the semiclassical approximation, a Boltzman-like equation is derived for the…

Condensed Matter · Physics 2016-08-31 Igor E. Aronov , Gennady P. Berman , David K. Campbell , Sergey V. Dudiy

We show that the conductance of neutral atoms through a tightly confining waveguide constriction is quantized in units of lambda_dB^2/pi, where lambda_dB is the de Broglie wavelength of the incident atoms. Such a constriction forms the atom…

Atomic Physics · Physics 2014-01-30 J. H. Thywissen , R. M. Westervelt , M. Prentiss

The 0.7 conductance anomaly in the quantized conductance of trench etched GaAs quantum point contacts is studied experimentally. The temperature dependence of the anomaly measured with vanishing source-drain bias reveals the same activated…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Kristensen , H. Bruus , A. Forchel , J. B. Jensen , P. E. Lindelof , M. Michel , J. Nygard , C. B. Sorensen

The transport properties of nanostructured systems are deeply affected by the geometry of the effective connections to metallic leads. In this work we derive a conductance expression for interacting systems whose connectivity geometries do…

Mesoscale and Nanoscale Physics · Physics 2017-09-15 Luis G. G. V. Dias da Silva , Caio H. Lewenkopf , Edson Vernek , Gerson J. Ferreira , Sergio E. Ulloa

The proximity-induced superconducting state in the 3-dimensional topological insulator HgTe has been studied using electronic transport of a normal metal-superconducting point contact as a spectroscopic tool (Andreev point contact…

Quantum spin transport is studied in an interacting quantum dot. It is found that a conductance "plateau" emerges in the non-linear charge conductance by a spin bias in the Kondo regime. The conductance plateau, as a complementary to the…

Mesoscale and Nanoscale Physics · Physics 2008-07-24 Yun-Juan Bao , Ning-Hua Tong , Qing-Feng Sun , Shun-Qing Shen

The $\nu = 2/3$ fractional quantum Hall state is the hole-conjugate state to the primary Laughlin $\nu = 1/3$ state. We investigate transmission of edge states through quantum point contacts fabricated on a GaAs/AlGaAs heterostructure…

Mesoscale and Nanoscale Physics · Physics 2023-03-01 James Nakamura , Shuang Liang , Geoffrey C. Gardner , Michael J. Manfra

We study the equilibrium properties of a quantum dot connected to a bulk lead by a single-mode quantum point contact. The ground state energy and other thermodynamic characteristics of the grain show periodic dependence on the gate voltage…

Condensed Matter · Physics 2009-10-22 K. A. Matveev

The connectivity within single carrier information-processing devices requires transport and storage of single charge quanta. Our all-electrical Si/SiGe shuttle device, called quantum bus (QuBus), spans a length of 10 $\mathrm{\mu}$m and is…

Mesoscale and Nanoscale Physics · Physics 2024-03-15 Ran Xue , Max Beer , Inga Seidler , Simon Humpohl , Jhih-Sian Tu , Stefan Trellenkamp , Tom Struck , Hendrik Bluhm , Lars R. Schreiber

Linear conductance below $2e^2/h$ shows resonance peaks in highly asymmetric quantum point contacts (QPCs). As the channel length increases, the number of peaks also increases. At the same time, differential conductance exhibits zero bias…

Mesoscale and Nanoscale Physics · Physics 2013-10-01 Hao Zhang , Phillip M. Wu , Albert M. Chang

We present a detailed study of the surface acoustic wave mediated quantized transport of electrons through a split gate device containing an impurity potential defined quantum dot within the split gate channel. A new regime of quantized…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 N. E. Fletcher , J. Ebbecke , T. J. B. M. Janssen , F. J. Ahlers , M. Pepper , H. E. Beere , D. A. Ritchie

A quantum point contact (QPC) is a very basic nano-electronic device: a short and narrow transport channel between two electron reservoirs. In clean channels electron transport is ballistic and the conductance $G$ is then quantised as a…