  A longstanding goal of spintronics is to inject, coherently transport, and
detect spins in a semiconductor nanowire where a SINGLE quantized subband is
occupied at room temperature. Here, we report achieving this goal in 50-nm
diameter InSb nanowires by demonstrating both the spin-valve and the Hanle
effect. The spin relaxation time in the nanowires was found to have increased
by an order of magnitude over what has been reported in bulk and quantum wells
due to the suppression of D'yakonov-Perel' spin relaxation as a result of
single subband occupancy. These experiments raise hopes for the realization of
a room-temperature Datta-Das spin transistor.
