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We report detailed transport measurements in a quantum dot in a spin-flip co-tunneling regime, and a quantitative comparison of the data to microscopic theory. The quantum dot is fabricated by lateral gating of a GaAs/AlGaAs…

Mesoscale and Nanoscale Physics · Physics 2012-07-31 Tai-Min Liu , Anh T. Ngo , Bryan Hemingway , Steven Herbert , Michael Melloch , Sergio E. Ulloa , Andrei Kogan

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…

We perform polarization-resolved magneto-optical measurements on single InAsP quantum dots embedded in an InP nanowire. In order to determine all elements of the electron and hole $g$-factor tensors, we measure in magnetic field with…

Materials Science · Physics 2011-12-06 B. J. Witek , R. W. Heeres , U. Perinetti , E. P. A. M. Bakkers , L. P. Kouwenhoven , V. Zwiller

We consider a superconducting quantum point contact in a circuit quantum electrodynamics setup. We study three different configurations, attainable with current technology, where a quantum point contact is coupled galvanically to a coplanar…

Superconductivity · Physics 2012-05-25 G. Romero , I. Lizuain , V. S. Shumeiko , E. Solano , F. S. Bergeret

We investigate the power dissipated by an electronic current flowing through a quantum point contact in a two-dimensional electron gas. Based on the Landauer-B\"uttiker approach to quantum transport, we evaluate the power that is dissipated…

Mesoscale and Nanoscale Physics · Physics 2022-03-30 Carmen Blaas-Anselmi , Félix Helluin , Rodolfo A. Jalabert , Guillaume Weick , Dietmar Weinmann

The transport properties of a magnetic two dimensional electron gas consisting of a modulation doped n type HgMnTe/HgCdTe quantum well, QW, have been investigated. By analyzing the Shubnikov-de Haas oscillations and the node positions of…

Strongly Correlated Electrons · Physics 2007-05-23 Y. S. Gui , C. R. Becker , J. Liu , V. Daumer , V. Hock , H. Buhmann , L. W. Molenkamp

We present numerical calculations of the conductance of an interface between a phase-coherent two-dimensional electron gas and a superconductor with a quantum point contact in the normal region. Using a scattering matrix approach we…

Superconductivity · Physics 2007-05-23 Niels Asger Mortensen , Antti-Pekka Jauho , Karsten Flensberg , Henning Schomerus

We solve two-dimensional model of $N$-component dense electron gas in the limit of large $N$ and in a range of the Coulomb interaction parameter: $N^{-3/2}\ll r_s\ll 1$. The quasiparticle interaction on the Fermi circle vanishes as 1/N. The…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 S. V. Iordanski , A. Kashuba

Coupling the spin degree of freedom to the anisotropic orbital motion of two-dimensional (2D) hole systems gives rise to a highly anisotropic Zeeman splitting with respect to different orientations of an in-plane magnetic field B relative…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 R. Winkler , S. J. Papadakis , E. P. De Poortere , M. Shayegan

We report excited-state spectroscopy on a quantum dot side-coupled to a quantum wire with accurate energy estimation. Our method utilizes periodic voltage pulses on the dot, and the energy calibration is performed with reference to the bias…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Tomohiro Otsuka , Eisuke Abe , Yasuhiro Iye , Shingo Katsumoto

We investigated the effect due to perpendicular magnetic field on quantum wires where spin-orbit interaction (SOI) of electrons is not neglected. Based on the calculated energy dispersion, the nonlinear ballistic conductance ($G$) and…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 Godfrey Gumbs , Antonios Balassis , Danhong Huang , Sheehan Ahmed , Ryan Brennan

We report on developing split-gate quantum point contacts (QPCs) that have a tunable length for the transport channel. The QPCs were realized in a GaAs/AlGaAs heterostructure with a two- dimensional electron gas (2DEG) below its surface.…

Mesoscale and Nanoscale Physics · Physics 2013-01-15 M. J. Iqbal , J. P. de. Jong , D. Reuter , A. D. Wieck , C. H. van der Wal

Scanning gate microscopy is used to locally investigate electron transport in a high-mobility two-dimensional electron gas formed in a GaAs/AlGaAs heterostructure. Using quantum point contacts (QPC) we observe branches caused by electron…

Mesoscale and Nanoscale Physics · Physics 2015-06-05 A. A. Kozikov , C. Rössler , T. Ihn , K. Ensslin , C. Reichl , W. Wegscheider

We present a study on the lifting of degeneracy of the size-quantized energy levels in an electrostatically defined quantum point contact in bilayer graphene by the application of in-plane magnetic fields. We observe a Zeeman spin splitting…

Mesoscale and Nanoscale Physics · Physics 2022-02-03 Vanessa Gall , Rainer Kraft , Igor V. Gornyi , Romain Danneau

A new fabrication technique is used to produce quantum dots with read-out channels in silicon/silicon-germanium two-dimensional electron gases. The technique utilizes Schottky gates, placed on the sides of a shallow etched quantum dot, to…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 M. R. Sakr , E. Yablonovitch , E. T. Croke , H. W. Jiang

We implement a microscopic spin filter for cold fermionic atoms in a quantum point contact (QPC) and create fully spin-polarized currents while retaining conductance quantization. Key to our scheme is a near-resonant optical tweezer…

The magnetic-field evolution of Coulomb blockade peaks in lateral InGaAs/InAlAs quantum dots in the few-electron regime is reported. Quantum dots are defined by gates evaporated onto a 60 nm-thick hydrogen silsesquioxane insulating film. A…

Mesoscale and Nanoscale Physics · Physics 2010-07-02 F. Deon , V. Pellegrini , F. Carillo , F. Giazotto , L. Sorba , G. Biasiol , F. Beltram

Images of electron flow through a two-dimensional electron gas from a quantum point contact (QPC) can be obtained at liquid He temperatures using scanning probe microscopy (SPM). A negatively charged SPM tip depletes the electron gas…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 B. J. LeRoy , A. C. Bleszynski , M. A. Topinka , R. M. Westervelt , S. E. J. Shaw , E. J. Heller , K. D. Maranowski , A. C. Gossard

Two tunnel-coupled few-electron quantum dots were fabricated in a GaAs/AlGaAs quantum well. The absolute number of electrons in each dot could be determined from finite bias Coulomb blockade measurements and gate voltage scans of the dots,…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 I. H. Chan , P. Fallahi , A. Vidan , R. M. Westervelt , M. Hanson , A. C. Gossard

We measured the magneto-reflectivity spectra (4 - 90 meV, 0 - 16 T) of the triple-point semimetal GdPtBi and found them to demonstrate two unusual broad features emerging in field. The electronic bands of GdPtBi are expected to experience…

Mesoscale and Nanoscale Physics · Physics 2023-11-15 S. Polatkan , E. Uykur , I. Mohelsky , J. Wyzula , M. Orlita , C. Shekhar , C. Felser , M. Dressel , A. V. Pronin
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