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We calculate the conductance of a quantum wire with two occupied subbands in a presence of a barrier taking into account the interaction between electrons. We extend the renormalization-group equation for the scattering matrix of the…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 A. V. Borin , K. E. Nagaev

We fabricated strongly confined Schottky-gated quantum point contacts by etching Si/SiGe heterostructures and observed intriguing conductance quantization in units of approximately 1e2/h. Non-linear conductance measurements were performed…

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

We study a single-mode cavity weakly coupled to a voltage-biased quantum point contact. In a perturbative analysis, the lowest order predicts a thermal state for the cavity photons, driven by the emission noise of the conductor. The cavity…

Mesoscale and Nanoscale Physics · Physics 2016-07-05 Udson C. Mendes , Christophe Mora

When the electron-phonon coupling is quadratic in the phonon coordinates, electrons can pair to form bipolarons due to phonon zero-point fluctuations, a purely quantum effect. We study superconductivity originating from this pairing…

Superconductivity · Physics 2024-09-18 Zhaoyu Han , Steven A. Kivelson , Pavel A. Volkov

The ab-initio theory of charge transport in semiconductors typically employs the lowest-order perturbation theory in which electrons interact with one phonon (1ph). This theory is accepted to be adequate to explain the low-field mobility of…

Materials Science · Physics 2023-02-08 Benjamin Hatanpää , Alexander Y. Choi , Peishi S. Cheng , Austin J. Minnich

We present new results of the ``0.7'' 2(e^2)/h structure or quasi plateau in some of the most strongly confined point contacts so far reported. This strong confinement is obtained by a combination of shallow etching and metal gate…

Short length quantum wires (quantum contacts) exhibit a conductance structure at the value of conductance close to 0.7 \times 2e^2/h. The structure is also called the conductance anomaly. In longer contacts the structure evolves to the…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 O. P. Sushkov

One-dimensional quantized conductance is derived from the electrons in a homogeneous electric field by calculating the traveling time of the accelerated motion and the number of electrons in the one-dimensional region. As a result, the…

Mesoscale and Nanoscale Physics · Physics 2024-12-25 Daiju Terasawa

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 calculate the electronic resistivity of a GaAs-based semiconductor quantum wire in the presence of acoustic phonon scattering. We find that the usual Drude-Boltzmann transport theory leads to a low temperature activated behavior instead…

Condensed Matter · Physics 2009-10-28 Lian Zheng , S. Das Sarma

A rate equation formalism is used to determine the effect of electron-phonon coupling on the conductance of a molecule. Interplay between the phonon-induced renormalization of the density of states on the quantum dot and the phonon-induced…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Mitra , I. Aleiner , A. J. Millis

A new non-ballistic analytical model for the intrinsic channel region of MOSFET-like single-walled carbon-nanotube field-effect transistors with ohmic contacts has been developed which overcomes the limitations of existing models and…

Mesoscale and Nanoscale Physics · Physics 2016-03-01 Igor Bejenari , Martin Claus

The relaxation of electrons in quantum dots via phonon emission is hindered by the discrete nature of the dot levels (phonon bottleneck). In order to clarify the issue theoretically we consider a system of $N$ discrete fermionic states (dot…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 T. Stauber , R. Zimmermann , H. Castella

We study the full-counting statistics of charges transmitted through a single-level quantum dot weakly coupled to a local Einstein phonon which causes fluctuations in the dot energy. An analytic expression for the cumulant generating…

Mesoscale and Nanoscale Physics · Physics 2013-03-12 Y. Utsumi , O. Entin-Wohlman , A. Ueda , A. Aharony

For unpolarized electrons in a clean quantum wire, density functional theory reveals a thermally activated suppression of conductance. The activation temperature T_A grows slowly (roughly quadratically) with gate voltage due to pinning of…

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

Optical phonons naturally generate linear-in-$T$ resistivity in the high-temperature equipartition regime, but their finite gap prevents this mechanism from surviving to asymptotically low temperatures. Here we analyze whether proximity to…

Strongly Correlated Electrons · Physics 2026-03-13 Haoyu Guo , Debanjan Chowdhury

In a nanomechanical resonator coupled to a quantum point contact, the back action of the electronic state on mechanical motion is studied. The quantum point contact conductance changing with subband index and the eigenfrequency of the…

Mesoscale and Nanoscale Physics · Physics 2024-05-24 Andrey A. Shevyrin , Askhat K. Bakarov , Alexander A. Shklyaev , Arthur G. Pogosov

The amplitude of magnetoresistance quantum oscillations of Al and Be point contacts in a magnetic field parallel to the contact axis has been studied as a function of voltage applied over the contact. It was found that for one group of…

Mesoscale and Nanoscale Physics · Physics 2016-01-05 N. L. Bobrov , J. A. Kokkedee , N. N. Gribov , I. K. Yanson , A. G. M. Jansen , P. Wyder

Long-distance transfer of quantum information in architectures based on quantum dot spin qubits will be necessary for their scalability. One way of achieving it is to simply move the electron between two quantum registers. Precise control…

Mesoscale and Nanoscale Physics · Physics 2021-08-25 Jan A. Krzywda , Łukasz Cywiński

A Quantum Point Contact (QPC) causes a one-dimensional constriction on the spatial potential landscape of a two-dimensional electron system. By tuning the voltage applied on a QPC at low temperatures the resulting regular step-like electron…

Mesoscale and Nanoscale Physics · Physics 2015-06-19 E. Schubert , J. Heyder , F. Bauer , W. Stumpf , W. Wegscheider , J. v. Delft , S. Ludwig , A. Högele