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Title: Valley-dependent spin polarization and long-lived electron spins in germanium

Spin orientation and relaxation of conduction band electrons in bulk Ge are addressed by studying the steady-state circular polarization of the indirect gap photoluminescence (PL) at low temperatures. This provides a direct experimental proof of recently predicted spin-dependent selection rules for phonon-mediated optical transitions in Ge. In addition, we observe valley-dependent circularly polarized emission, and map the concomitant redistribution of electron spins within the multi-valley conduction band of Ge by gaining simultaneous access to the circular dichroism of light emitted across the direct and the indirect gap transitions. Finally, the lifetime of L-valley electrons is measured by means of decay curves of the indirect gap PL emission, yielding spin relaxation times in the order of hundreds of ns.
Authors:
; ; ; ;  [1]
  1. LNESS and Dipartimento di Scienza dei Materiali, Università degli Studi di Milano-Bicocca, via Cozzi 55, I-20125 Milano (Italy)
Publication Date:
OSTI Identifier:
22350903
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 15; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DICHROISM; ELECTRONS; GAIN; GERMANIUM; LIFETIME; PHONONS; PHOTOLUMINESCENCE; POLARIZATION; RELAXATION; SELECTION RULES; SPIN; SPIN ORIENTATION; STEADY-STATE CONDITIONS; VISIBLE RADIATION