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We have developed a novel technique for detection of spin polarization with a quantum dot weakly coupled to the objective device. The disturbance to the object in this technique is very small since the detection is performed through…

Mesoscale and Nanoscale Physics · Physics 2016-12-21 Sunwoo Kim , Yoshiaki Hashimoto , Taketomo Nakamura , Shingo Katsumoto

Semiconductor point contacts can be a useful tool for producing spin-polarized currents in the presence of spin-orbit (SO) interaction. Neither magnetic fields nor magnetic materials are required. By numerical studies, we show that (i) the…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 Mikio Eto , Tetsuya Hayashi , Yuji Kurotani

We report the observation of an anomalous conductance plateau near G = 0.5 G0 (G0 = 2e2/h) in asymmetrically biased AlGaAs/GaAs quantum point contacts (QPCs), with in-plane side gates in the presence of lateral spin-orbit coupling. This is…

Mesoscale and Nanoscale Physics · Physics 2012-04-24 N. Bhandari , P. P. Das , M. Cahay , R. S. Newrock , S. T. Herbert

We demonstrate a mesoscopic spin polarizer/analyzer system that allows the spin polarization of current from a quantum point contact in an in-plane magnetic field to be measured. A transverse focusing geometry is used to couple current from…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 R. M. Potok , J. A. Folk , C. M. Marcus , V. Umansky

We propose realistic methods to detect local spin polarization, which utilize a quantum dot side coupled to the target system. By choosing appropriate states in the dot, we can put spin selectivity to the dot and detect spins in the target…

Mesoscale and Nanoscale Physics · Physics 2011-06-14 Tomohiro Otsuka , Eisuke Abe , Yasuhiro Iye , Shingo Katsumoto

We study ballistic transport through semiconductor quantum point contact systems under different confinement geometries and applied fields. In particular, we investigate how the {\em lateral} spin-orbit coupling, introduced by asymmetric…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Anh T. Ngo , P. Debray , Sergio Ulloa

Nuclear spin polarization is typically generated in GaAs quantum point contacts (QPCs) when an out-of-plane magnetic field gives rise to spin-polarized quantum Hall edge states, and a voltage bias drives transitions between the edge states…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Y. Ren , W. Yu , S. M. Frolov , J. A. Folk , W. Wegscheider

The spin polarization of electrons trapped in InAs self-assembled quantum dot ensembles is investigated. A statistical approach for the population of the spin levels allows one to infer the spin polarization from the measure values of the…

Materials Science · Physics 2008-04-04 F. G. G. Hernandez , T. P. Mayer Alegre , G. Medeiros-Ribeiro

We theoretically investigate the dynamical nuclear spin polarization in a quantum point contact (QPC) at finite magnetic field. We find that when the QPC is tuned to be spin selective, at the conductance of e^2/h, a finite bias induces a…

Mesoscale and Nanoscale Physics · Physics 2018-03-20 Peter Stano , Tomosuke Aono , Minoru Kawamura

It has been predicted recently that an electron beam can be polarized when it flows adiabatically through a quantum point contact in a system with spin-orbit interaction. Here, we show that a simple transverse electron focusing setup can be…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. Reynoso , Gonzalo Usaj , C. A. Balseiro

Self-consistent modelling based on local spin-density formalism is employed to calculate conductance of quantum point contacts at finite temperatures. The total electrostatic potential exhibits spin-dependent splitting, which persists at…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 A. M. Bychkov , T. M. Stace

We propose a new method for dynamic nuclear polarisation in a quasi one-dimensional quantum wire utilising the spin-orbit interaction, the hyperfine interaction, and a finite source-drain potential difference. In contrast with current…

Mesoscale and Nanoscale Physics · Physics 2008-03-05 V. Tripathi , A. C. H. Cheung , N. R. Cooper

We analyze the conductance of the quantum point contact containing large localized spin J. The additional plateau is formed on a ballistic conductance staircase if only one propagating channel is rendered conducting. The conductance value…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 I. A. Shelykh , N. G. Galkin , N. T. Bagraev

We report electrical control of the spin polarization of InAs/GaAs self-assembled quantum dots (QDs) at room temperature. This is achieved by electrical injection of spin-polarized electrons from an Fe Schottky contact. The circular…

Quantum point contacts implemented in p-type GaAs/AlGaAs heterostructures are investigated by low-temperature electrical conductance spectroscopy measurements. Besides one-dimensional conductance quantization in units of $2e^{2}/h$ a…

Mesoscale and Nanoscale Physics · Physics 2013-01-22 Y. Komijani , M. Csontos , I. Shorubalko , T. Ihn , K. Ensslin , Y. Meir , D. Reuter , A. D. Wieck

We report on the dynamic nuclear polarization of a single charge-tunable self-assembled InAs/GaAs quantum dot in a longitudinal magnetic field of $\sim$0.2T. The hyperfine interaction between the optically oriented electron and nuclei spins…

By using the Nambu-Jona-Lasinio model with a tensor-type four-point interaction between quarks, it is shown that there exists a possibility of a spin polarized phase in quark matter at finite temperature and density. When there exists the…

High Energy Physics - Phenomenology · Physics 2017-03-14 Y. Tsue , J. da Providencia , C. Providencia , H. Matsuoka , M. Yamamura , H. Bohr

We describe how a local non-equilibrium nuclear polarisation can be generated and detected by electrical means in a semiconductor quantum point contact device. We show that measurements of the nuclear spin relaxation rate will provide clear…

Mesoscale and Nanoscale Physics · Physics 2008-06-26 N. R. Cooper , V. Tripathi

The conditions for a spontaneous spin polarization in a quantum wire positioned in a zero magnetic field are analyzed under weak population of one-dimensional subbands that gives rise to the efficient quenching of the kinetic energy by the…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 N. T. Bagraev , V. K. Ivanov , L. E. Klyachkin , I. A. Shelykh

We study spin polarization in a split-gate quantum wire focussing on the effect of a realistic smooth potential due to remote donors. Electron interaction and spin effects are included within the density functional theory in the local spin…

Mesoscale and Nanoscale Physics · Physics 2008-04-04 M. Evaldsson , S. Ihnatsenka , I. V. Zozoulenko
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