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HL: Halbleiterphysik
HL 41: Ultrakurzzeitph
änomene II
HL 41.5: Vortrag
Freitag, 30. März 2001, 12:30–12:45, S9/10
Spin coherence and spin dephasing in GaN — •B. Beschoten1,2, E. Johnston-Halperin2, D.K. Young1,3, J.E. Grimaldi1, S. Keller3, S.B. DenBaars3,4, U.K. Mishra3, E.L. Hu3, D.D. Awschalom1, and 5 — 1Department of Physics, University of California, Santa Barbara, California 93106 — 22. Physikalisches Institut, RWTH Aachen, Templergraben 55, 52056 Aachen, Germany — 3Electrical and Computer Engineering, University of California, Santa Barbara, California 93106 — 4Materials Department, University of California, Santa Barbara, California 93106 — 5
Recent observations of extremely long spin coherence times
for optically injected spins in non-magnetic semiconductors
have raised the possibility that these spin-coherent properties
may eventually enable quantum computational operations in
solid state systems.
In this context, the III-V semiconductor GaN is intriguing in that
it combines a high density of charged threading dislocations
(typically 108 - 1010 cm−2), with high optical quality.
Here we use time-resolved Faraday rotation to measure
electron spin coherence in n-type GaN epilayers. Despite the high
densities of dislocations, this coherence yields spin
lifetimes of ∼20 ns at T=5 K and persists to room temperature.
Spin dephasing is investigated in the vicinity of the
metal-insulator transition [1]. The dependence on both magnetic
field and temperature is found to be qualitatively similar to
previous studies in n-type GaAs, suggesting a common origin for
spin relaxation in these systems.
[1] B. Beschoten et al., Phys. Rev. B, RC (in press).