Thursday's seminar

[Regional School on Physics at Nanoscale Vietnam]

SEMINAR on    Disorder and strong electron correlations



Thursday, 8 October      -  11:00 a.m.



Seminar Room,  Leonardo Building - first floor



B. TRAUZETTEL    ( Universität Würzburg )



  "Phase-coherent transport in   2D topological insulators"



Abstract



We investigate an effective low energy theory of HgTe quantum wells  
near their mass inversion thickness in a perpendicular magnetic  
field.  By comparison of the effective band structure with a more  
elaborated and well-established model, the parameter regime and the  
validity of the effective model are quantified.  Optical transitions  
(between Landau levels) in HgTe quantum wells are analyzed.  We find  
selection rules which we functionalize to optically manipulate edge  
state transport. [1]  In the absence of magnetic fields, the ballistic  
transport through HgTe quantum wells in the so-called inverted regime  
is believed to be dominated by edge state transport.  The existence of  
these edge states (at zero magnetic field) is one of the hallmarks of  
topological insulators. We show that transport through the gapped bulk  
via evanescent modes can in general not be neglected in ballistic HgTe  
quantum wells.



[1] M.J. Schmidt, E.G. Novik, M. Kindermann, and B. Trauzettel, Phys.  
Rev. B 79, 241306(R) (2009)