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By operating a one-electron quantum dot (fabricated between a multielectron dot and a one-electron reference dot) as a spectroscopic probe, we study the spin properties of a gate-controlled multielectron GaAs quantum dot at the transition…

We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs/GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. P. Weber , J. Orenstein , B. Andrei Bernevig , Shou-Cheng Zhang , Jason Stephens , D. D. Awschalom

We investigate the spin of a multielectron GaAs quantum dot in a sequence of nine charge occupancies, by exchange coupling the multielectron dot to a neighboring two-electron double quantum dot. For all nine occupancies, we make use of a…

There is controversy as to whether a one-dimensional (1D) electron gas can spin polarise in the absence of a magnetic field. Together with a simple model, we present conductance measurements on ultra low-disorder quantum wires supportive of…

Strongly Correlated Electrons · Physics 2007-05-23 D. J. Reilly , T. M. Buehler , J. L. O'Brien , A. R. Hamilton , A. S. Dzurak , R. G. Clark , B. E. Kane , L. N. Pfeiffer , K. W. West

A quantitative investigation of spin-pumping-induced spin-transport in n-GaAs was conducted at room temperature (RT). GaAs has a non-negligible spin orbit interaction, so that electromotive force due to the inverse spin Hall effect (ISHE)…

Materials Science · Physics 2015-06-23 Akiyori Yamamoto , Yuichiro Ando , Teruya Shinjo , Tetsuya Uemura , Masashi Shiraishi

We present a new way of continuously reading-out the state of a single electronic spin. Our detection scheme is based on an exchange interaction between the electronic spin and a nearby read-out quantum dot. The coupling between the two…

Mesoscale and Nanoscale Physics · Physics 2017-11-21 Clément Godfrin , Stefan Thiele , Karim Ferhat , Svetlana Klyatskaya , Mario Ruben , Wolfgang Wernsdorfer , Franck Balestro

We report conductance measurements of a ballistic one-dimensional (1D) wire defined in the lower two-dimensional electron gas of a GaAs/AlGaAs double quantum well. At low temperatures there is an additional structure at $0.7(2e^2/h)$ in the…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 K. J. Thomas , J. T. Nicholls , M. Pepper , W. R. Tribe , M. Y. Simmons , D. A. Ritchie

We explore electrically injected, spin polarized transport in a ballistic two-dimensional electron gas. We augment the Buettiker-Landauer picture with a simple, but realistic model for spin-selective contacts to describe multimode…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 H. X. Tang , F. G. Monzon , Ron Lifshitz , M. C. Cross , M. L. Roukes

We report electronic control and measurement of an imbalance between spin-up and spin-down electrons in micron-scale open quantum dots. Spin injection and detection was achieved with quantum point contacts tuned to have spin-selective…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 E. J. Koop , B. J. van Wees , D. Reuter , A. D. Wieck , C. H. van der Wal

We have investigated the transport properties of one-dimensional (1D) constrictions defined by split-gates in high quality GaAs/AlGaAs heterostructures. In addition to the usual quantized conductance plateaus, the equilibrium conductance…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 K. J. Thomas , J. T. Nicholls , N. J. Appleyard , M. Pepper , M. Y. Simmons , D. R. Mace , W. R. Tribe , D. A. Ritchie

We report selective injection of both spin-up and spin-down single electrons into a quantum dot (QD) from spin-polarized non-equilibrium quantum Hall edge channels (ECs) generated by selective transmission of spin-resolved ECs using a…

Mesoscale and Nanoscale Physics · Physics 2015-06-24 Haruki Kiyama , Takashi Nakajima , Soichiro Teraoka , Akira Oiwa , Seigo Tarucha

We investigate a one--dimensional wire of interacting electrons connected to one--dimensional noninteracting leads in the absence and in the presence of a backscattering potential. The ballistic wire separates the charge and spin parts of…

Strongly Correlated Electrons · Physics 2009-10-31 Inès Safi , H. J. Schulz

We have measured the collective excitation spectrum of interacting electrons in one-dimension. The experiment consists of controlling the energy and momentum of electrons tunneling between two clean and closely situated, parallel quantum…

The emission of circularly polarized light from a single quantum dot relies on the injection of carriers with well-defined spin polarization. Here we demonstrate single dot electroluminescence (EL) with a circular polarization degree up to…

We present a proposal for a fully electrically controllable quantum dot based spin current injector. The device consists of a quantum dot that is strongly coupled to a ferromagnetic electrode on one side and weakly coupled to a nonmagnetic…

Mesoscale and Nanoscale Physics · Physics 2012-10-23 Szabolcs Csonka , Ireneusz Weymann , Gergely Zarand

We study electron spin dynamics whose movement is restricted to the lowest one dimensional subband channel ($G \le 2e^2/h $), through nuclear spin relaxation rate measurement ($1/T_1$). We observe an unusual double-peak structure in the…

Mesoscale and Nanoscale Physics · Physics 2024-11-27 M. H. Fauzi , M. Takahashi , T. Aono , K. Hashimoto , Y. Hirayama

We use time-resolved Faraday rotation to measure coherent spin dynamics in colloidal CdSe quantum dots charged in an electrochemical cell at room temperature. Filling of the 1Se electron level is demonstrated by the bleaching of the…

Other Condensed Matter · Physics 2007-05-23 N. P. Stern , M. Poggio , M. H. Bartl , E. L. Hu , G. D. Stucky , D. D. Awschalom

We report an all-electric integrable electron focusing lens in n-type GaAs. It is shown that a pronounced focusing peak takes place when the focal point aligns with an on-chip detector. The intensity and full width half maximum (FWHM) of…

Mesoscale and Nanoscale Physics · Physics 2020-02-14 Chengyu Yan , Michael Pepper , Patrick See , Ian Farrer , David Ritchie , Jonathan Griffiths

The superposition of complex optical fields in three-dimension (3D) is the basis of several non-trivial wave phenomena. Significant among them are the non-uniform polarization distribution and their topological character, leading to the…

Optics · Physics 2024-10-01 Nitish Kumar , Cyriac Raju , Dinesh N. Naik , Nirmal K. Viswanathan

We report spin amplification using a capacitive beam splitter in n-type GaAs where the spin polarization is monitored via transverse electron focusing measurement. It is shown that partially spin-polarized current injected by the emitter…

Mesoscale and Nanoscale Physics · Physics 2018-03-29 Chengyu Yan , Sanjeev Kumar , Kalarikad Thomas , Patrick See , Ian Farrer , David Ritchie , Jonathan Griffiths , Geraint Jones , Michael Pepper