Enhanced spin-polarization lifetimes in a two-dimensional electron gas in a gate-controlled GaAs quantum well

Sergiu Anghel, Akshay Singh, Felix Passmann, Hikaru Iwata, John N. Moore, Go Yusa, Xiaoqin Li, and Markus Betz
Phys. Rev. B 94, 035303 – Published 18 July 2016
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Abstract

Exciton, trion, and electron spin dynamics in a 20-nm-wide modulation-doped GaAs single quantum well are investigated using resonant ultrafast two-color Kerr rotation spectroscopy. Excitons and trions are selectively detected by resonant probe pulses while their relative spectral weight is controlled by adjusting the gate voltage which tunes the carrier density. Tuning the carrier density markedly influences the spin decay time of the two-dimensional electron gas. The spin decay time can be enhanced by a factor of 3 at an intermediate carrier concentration in the quantum well where excitons and trions coexist in the system. In addition, we explore the capability to tune the g factor of the electron gas via the carrier density.

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  • Received 2 May 2016
  • Revised 20 June 2016

DOI:https://doi.org/10.1103/PhysRevB.94.035303

©2016 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Sergiu Anghel1, Akshay Singh2, Felix Passmann1, Hikaru Iwata3, John N. Moore3, Go Yusa3, Xiaoqin Li2,4, and Markus Betz1,*

  • 1Experimentelle Physik 2, Technische Universität Dortmund, Otto-Hahn-Straße 4a, D-44227 Dortmund, Germany
  • 2Department of Physics and CQS, University of Texas at Austin, Austin, Texas 78712, USA
  • 3Department of Physics, Tohoku University, Sendai 980-8578, Japan
  • 4Texas Materials Institute, University of Texas at Austin, Austin, Texas 78712, USA

  • *markus.betz@tu-dortmund.de

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Issue

Vol. 94, Iss. 3 — 15 July 2016

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