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SUMMARY:Large out-of-plane g-factor for quasi 2D holes in GaAs heterostruc
 tures - Mr Ashwin Srinivasan\, School of Physics\, University of New South
  Wales\, Sydney\, Australia
DTSTART:20110819T131500Z
DTEND:20110819T150000Z
UID:TALK32516@talks.cam.ac.uk
CONTACT:Emma Faid
DESCRIPTION:The spin of charge carriers provides an additional degree of f
 reedom to charge for storing and processing information. One avenue for ac
 hieving such control of spin is through the phenomenon of spin-orbit coupl
 ing in low dimensional hole based GaAs heterostructures. Due to the strong
  spin-orbit interaction in the valence band\, spatially confining holes in
  these heterostructures also influences spin. For example it has been theo
 retically predicted that for heavy holes confined to a 2D plane in (100) G
 aAs\, the effective Lande g-factor g* = 0 for an in-plane field\, but g* =
  7.2 for an out-of-plane field. This large anisotropy of the Landé g-fact
 or for holes in GaAs has been established theoretically for over two decad
 es. However\, despite numerous attempts over the past 20 years\, no report
 ed experiment has yet been able to measure a value close to the predicted 
 g-factor of g =7.2. In this work we attempt to corroborate the long standi
 ng theory by directly measuring g* electrically. However measuring the Zee
 man splitting in 2D systems is not possible\, as there are no spectroscopi
 c tools available. Instead we use a 1D wire\, and investigate the limiting
  behaviour as it becomes two-dimensional. The quantum wire allows us to pe
 rform energy spectroscopy and directly observe the Zeeman splitting as a f
 unction of magnetic field. We find a large anisotropy (g*_perp/g*|| > 5) i
 n agreement with theoretical expectations. For n=5\, we measure g* ~ 5\, w
 hich is approaching the theoretical 2D limit of 7.2.\n
LOCATION:Mott Seminar Room\, Cavendish Laboratory\, Department of Physics
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