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Full counting statistics of electron transport is of fundamental importance for a deeper understanding of the underlying physical processes in quantum transport in nanoscale devices. The backaction effect from a detector on the nanoscale…

Mesoscale and Nanoscale Physics · Physics 2013-11-01 Zeng-Zhao Li , Chi-Hang Lam , Ting Yu , J. Q. You

We report on the fabrication and electronic transport characterisation of Schottky-gated strongly confined Si/SiGe quantum point contacts (QPC). At zero magnetic field and T=450mK the QPC conductance as a function of gate voltage shows a…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 G. Scappucci , L. Di Gaspare , E. Giovine , A. Notargiacomo , R. Leoni , F. Evangelisti

We study electronic transport through a quantum point contact, where the interaction between the electrons is approximated by a contact potential. Our numerical approach is based on the non-equilibrium Green function technique which is…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Andreas Lassl , Peter Schlagheck , Klaus Richter

Quantum point contact or QPC -- a constriction in a semiconducting two-dimensional (2D) electron system with a quantized conductance -- has been found as the building block of novel spintronic, and topological electronic circuits. They can…

We propose a theoretical model for the low-frequency noise observed in a quantum point contact (QPC) electrostatically defined in the 2D electron gas at a GaAs-AlGaAs interface. In such contacts electron scattering by soft impurity- or…

Condensed Matter · Physics 2009-10-22 J. P. Hessling , Yu. Galperin , M. Jonson , R. I. Shekhter , A. M. Zagoskin

We investigate transport through a single-level quantum dot coupled to noncollinearly magnetized ferromagnets in the presence of localized spins in either the tunnel barrier or on the quantum dot. For a spin embedded in the tunnel barrier,…

Mesoscale and Nanoscale Physics · Physics 2010-12-24 Björn Sothmann , Jürgen König

Electron charge transport through a quantum point contact (QPC) driven by an asymmetric spin bias is studied. A large charge current is induced when the transmission coefficient of the QPC jumps from one integer plateau to the next.…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Yanxia Xing , Qing-feng Sun , Jian Wang

The phenomenology of the "0.7 anomaly" in quantum point contacts is fully explained in terms of a quasi-localized state, which forms as the point contact opens up. Detailed numerical calculations within spin-density functional theory indeed…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Yigal Meir

A non-equilibrium Green's function formalism is used to study in detail the ballistic conductance of asymmetrically biased side-gated quantum point contacts (QPCs) in the presence of lateral spin-orbit coupling and electron-electron…

Mesoscale and Nanoscale Physics · Physics 2010-10-01 J. Wan , M. Cahay , P. Debray , R. S. Newrock

Experiments on quantum point contacts have highlighted an anomalous conductance plateau at $0.7 (2e^2/h)$, with features suggestive of the Kondo effect. Here we present an Anderson model for transport through a point contact which we…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Yigal Meir , Kenji Hirose , Ned S. Wingreen

We present a simple phenomenological model which offers a unifying interpretation of the experimental observations on the 0.7 conductance anomaly of quantum point contacts. The model utilizes the Landauer-Buttiker formalism and involves…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Henrik Bruus , Vadim V. Cheianov , Karsten Flensberg

We analyze an AC-driven dimer chain connected to a strongly biased electron source and drain. It turns out that the resulting transport exhibits fingerprints of topology. They are particularly visible in the driving-induced current…

Mesoscale and Nanoscale Physics · Physics 2016-10-18 Michael Niklas , Mónica Benito , Sigmund Kohler , Gloria Platero

We studied ballistic transport across a quantum point contact (QPC) defined in a high-quality, GaAs (311)A two-dimensional (2D) hole system using shallow etching and top-gating. The QPC conductance exhibits up to 11 quantized plateaus. The…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 J. Shabani , J. R. Petta , M. Shayegan

In this work we study the particle conductance of a strongly interacting Fermi gas through a quantum point contact. With an atom-molecule two-channel model, we compute the contribution to particle conductance by both the fermionic atoms and…

Quantum Gases · Physics 2017-02-08 Boyang Liu , Hui Zhai , Shizhong Zhang

We theoretically study the spin current and its dc noise generated between two spin-1/2 spin chains weakly coupled at a single site in the presence of an over-population of spin excitations and a temperature elevation in one subsystem…

Mesoscale and Nanoscale Physics · Physics 2018-01-31 Joshua Aftergood , So Takei

In this paper, we present theoretical investigation of the zero-frequency shot noise spectra in electron tunneling through an interacting quantum dot connected to two ferromagnetic leads with possibility of spin-flip scattering between the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Ivana Djuric , Bing Dong , H. L. Cui

There exists a fascinating dual representation of the electric ac current flowing through a normal conductor. On the one hand, it can be understood in terms of charge transport. On the other hand, it consists in an electomagnetic field…

Mesoscale and Nanoscale Physics · Physics 2017-03-01 Jean Olivier Simoneau , Stéphane Virally , Christian Lupien , Bertrand Reulet

We calculate the mode-dependent transmission probability of massless Dirac fermions through an ideal strip of graphene (length L, width W, no impurities or defects), to obtain the conductance and shot noise as a function of Fermi energy. We…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 J. Tworzydlo , B. Trauzettel , M. Titov , A. Rycerz , C. W. J. Beenakker

We study the effects of electron-phonon interactions on the transport properties of a molecular quantum dot coupled to two Luttinger-liquid leads. In particular, we investigate the effects on the steady state current and DC noise…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 So Takei , Yong Baek Kim , Aditi Mitra

We report a zero-bias peak in the differential conductance of a Quantum Point Contact (QPC), which splits in an external magnetic field. The peak is observed over a range of device conductance values starting significantly below $2e^2/h$.…

Mesoscale and Nanoscale Physics · Physics 2011-08-22 Tai-Min Liu , Bryan Hemingway , Andrei Kogan , Steven Herbert , Michael Melloch