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Title: Weak anti-localization of two-dimensional holes in germanium beyond the diffusive regime

Abstract

Gate-controllable spin-orbit coupling is often one requisite for spintronic devices. For practical spin field-effect transistors, another essential requirement is ballistic spin transport, where the spin precession length is shorter than the mean free path such that the gate-controlled spin precession is not randomized by disorder. In this letter, we report the observation of a gate-induced crossover from weak localization to weak anti-localization in the magneto-resistance of a high-mobility twodimensional hole gas in a strained germanium quantum well. From the magneto-resistance, we extract the phase-coherence time, spin-orbit precession time, spin-orbit energy splitting, and cubic Rashba coefficient over a wide density range. The mobility and the mean free path increase with increasing hole density, while the spin precession length decreases due to increasingly stronger spin-orbit coupling. As the density becomes larger than , 6 x 10 11cm -2, the spin precession length becomes shorter than the mean free path, and the system enters the ballistic spin transport regime. We also report here the numerical methods and code developed for calculating the magnetoresistance in the ballistic regime, where the commonly used HLN and ILP models for analyzing weak localization and anti-localization are not valid. These results pave the way toward siliconcompatible spintronic devices.

Authors:
 [1];  [2];  [2];  [2];  [1];  [1];  [3]; ORCiD logo [2]
  1. National Taiwan Univ., Taipei (Taiwan)
  2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
  3. National Taiwan Univ., Taipei (Taiwan); National Nano Device Labs., Hsinchu (Taiwan)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1477314
Alternate Identifier(s):
OSTI ID: 1474007
Report Number(s):
SAND-2018-10483J
Journal ID: ISSN 2040-3364; 668122
Grant/Contract Number:  
AC04-94AL85000
Resource Type:
Accepted Manuscript
Journal Name:
Nanoscale
Additional Journal Information:
Journal Volume: 10; Journal Issue: 44; Journal ID: ISSN 2040-3364
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Chou, C. -T., Jacobson, N. T., Moussa, J. E., Baczewski, A. D., Chuang, Y., Liu, C. -Y., Li, J. -Y., and Lu, T. M. Weak anti-localization of two-dimensional holes in germanium beyond the diffusive regime. United States: N. p., 2018. Web. doi:10.1039/C8NR05677C.
Chou, C. -T., Jacobson, N. T., Moussa, J. E., Baczewski, A. D., Chuang, Y., Liu, C. -Y., Li, J. -Y., & Lu, T. M. Weak anti-localization of two-dimensional holes in germanium beyond the diffusive regime. United States. doi:10.1039/C8NR05677C.
Chou, C. -T., Jacobson, N. T., Moussa, J. E., Baczewski, A. D., Chuang, Y., Liu, C. -Y., Li, J. -Y., and Lu, T. M. Tue . "Weak anti-localization of two-dimensional holes in germanium beyond the diffusive regime". United States. doi:10.1039/C8NR05677C. https://www.osti.gov/servlets/purl/1477314.
@article{osti_1477314,
title = {Weak anti-localization of two-dimensional holes in germanium beyond the diffusive regime},
author = {Chou, C. -T. and Jacobson, N. T. and Moussa, J. E. and Baczewski, A. D. and Chuang, Y. and Liu, C. -Y. and Li, J. -Y. and Lu, T. M.},
abstractNote = {Gate-controllable spin-orbit coupling is often one requisite for spintronic devices. For practical spin field-effect transistors, another essential requirement is ballistic spin transport, where the spin precession length is shorter than the mean free path such that the gate-controlled spin precession is not randomized by disorder. In this letter, we report the observation of a gate-induced crossover from weak localization to weak anti-localization in the magneto-resistance of a high-mobility twodimensional hole gas in a strained germanium quantum well. From the magneto-resistance, we extract the phase-coherence time, spin-orbit precession time, spin-orbit energy splitting, and cubic Rashba coefficient over a wide density range. The mobility and the mean free path increase with increasing hole density, while the spin precession length decreases due to increasingly stronger spin-orbit coupling. As the density becomes larger than , 6 x 1011cm-2, the spin precession length becomes shorter than the mean free path, and the system enters the ballistic spin transport regime. We also report here the numerical methods and code developed for calculating the magnetoresistance in the ballistic regime, where the commonly used HLN and ILP models for analyzing weak localization and anti-localization are not valid. These results pave the way toward siliconcompatible spintronic devices.},
doi = {10.1039/C8NR05677C},
journal = {Nanoscale},
number = 44,
volume = 10,
place = {United States},
year = {2018},
month = {9}
}

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