2009 APS March Meeting
Volume 54, Number 1
Monday–Friday, March 16–20, 2009;
Pittsburgh, Pennsylvania
Session X3: Spin Hall and Quantum Spin Hall Effects
2:30 PM–5:30 PM,
Thursday, March 19, 2009
Room: 301/302
Sponsoring
Unit:
DCMP
Chair: David Awschalom, University of California, Santa Barbara
Abstract ID: BAPS.2009.MAR.X3.1
Abstract: X3.00001 : Imaging electrical spin generation and spin Hall dynamics in semiconductors*
2:30 PM–3:06 PM
Preview Abstract
Abstract
Author:
N.P. Stern
(Center for Spintronics and Quantum Computation, University of California, Santa Barbara, CA 93106)
The capability to generate and manipulate spin polarization
through the spin-orbit interaction drives interest in
all-electrical techniques to exploit electron spins for
semiconductor spintronics. The spin Hall effect refers to the
generation of a pure spin current transverse to a charge current,
resulting in a spontaneous spin accumulation near sample
boundaries without the need for magnetic fields or materials.
Recent experiments toward imaging this electrically generated
spin polarization with both spatially and temporally resolved
Kerr rotation microscopy in bulk zincblende semiconductors are
discussed. Both current-induced in-plane spin polarization and
out-of-plane spin accumulation from the spin Hall effect are
observed in ZnSe up to room temperature\footnote{N. P. Stern, S.
Ghosh, G. Xiang, M. Zhu, N. Samarth, and D. D. Awschalom,
\textit{Phys. Rev. Lett.} \textbf{97}, 126603 (2006)}. In GaAs
devices, spatially resolved measurements of steady-state spin
Hall accumulation and associated modeling clarify the important
role of drift and diffusion in transporting spins generated at
sample boundaries to the device interior\footnote{N. P. Stern, D.
W. Steuerman, S. Mack, A. C. Gossard, and D. D. Awschalom,
\textit{Appl. Phys. Lett.} \textbf{91}, 062109 (2007)}. In these
typical optical experiments, electrically-generated spin
accumulation is measured using steady-state techniques that do
not directly observe dynamics at timescales important for device
operation. Here we discuss a time- and spatially-resolved
measurement of the spin Hall effect using a pulsed current to
drive spin accumulation\footnote{N. P. Stern, D. W. Steuerman, S.
Mack, A. C. Gossard, and D. D. Awschalom, \textit{Nat. Physics}
\textbf{4}, 843 (2008)}. The dynamical processes of spin
accumulation and diffusion reveal spatially-dependent nanosecond
timescales comparable to the electric-field dependent spin
coherence time. A time-dependent diffusion analysis reconciles
the observed spatial and temporal dynamics of spin accumulation
from the spin Hall effect in one coherent picture.
*Work supported by NSF, ONR, and the Hertz Foundation.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2009.MAR.X3.1