Thursday, March 8, 2012

1203.1491 (W. Beugeling et al.)

Reentrant topological phases in Mn-doped HgTe quantum wells    [PDF]

W. Beugeling, C. X. Liu, E. G. Novik, L. W. Molenkamp, C. Morais Smith
Quantum wells of HgTe doped with Mn display the quantum anomalous Hall effect due to the magnetic moments of the Mn ions. In the presence of a magnetic field, these magnetic moments induce an effective nonlinear Zeeman effect, causing a nonmonotonic bending of the Landau levels. As a consequence, the quantized (spin) Hall conductivity exhibits a reentrant behavior as one increases the magnetic field. Here, we will discuss the appearance of different types of reentrant behavior as a function of Mn concentration, well thickness, and temperature, based on the qualitative form of the Landau-level spectrum in an effective four-band model.
View original: http://arxiv.org/abs/1203.1491

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