SEMINAR on Disorder and strong electron correlations: "Spin Hall effects in HgTe Quantum Well Structures"

[CM ICTP - Trieste]

CONDENSED MATTER SECTION

	
SEMINAR on

Disorder and strong electron correlations





Thursday, 6 December   -    16:00 hrs.



Seminar Room,  Main Building - First floor





L. W. MOLENKAMP
(Universität Würzburg)





"Spin Hall effects in HgTe
Quantum Well Structures"


Abstract
Spin-orbit interaction (SOI) in 2DEGs causes many interesting and 
potentially useful effects, such as the generation of an intrinsic spin 
accumulation polarized normal to the 2DEG at the edges, caused by the 
presently very topical spin-Hall effect [1]. So far no direct evidence 
for the intrinsic SHE has been obtained by transport experiments. Here, 
we demonstrate that in specially designed nanostructures [2], which are 
  based on narrow gap HgTe type-III quantum wells (QW), a detection of 
the spin  signal is possible via voltage measurements.
Recently, it was pointed out that inverted HgTe QW structurescan be 
regarded as non-trivial insulators[3], in which the quantum spin Hall 
insulator state[4]  should occur. In this state, a pair of spin 
polarized helical edge channels  develops when the bulk of the material 
is insulating, leading to a quantized  conductance. We will discuss our 
recent transport measurements on gated low  density HgTe QWs that yield 
a first evidence for the existence of this effect.