Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 6: TR: Nanoelectronics II: Spintronics and Magnetotransport

TT 6.6: Vortrag

Montag, 22. März 2010, 15:15–15:30, H19

Bulk transport properties of two-dimensional HgTe nanostructures — •Elena G. Novik¹, Patrik Recher², Ewelina M. Hankiewicz², and Björn Trauzettel² — ¹Physikalisches Institut (EP3), University of Würzburg, 97074 Würzburg — ²Institut für Theoretische Physik und Astrophysik, University of Würzburg, 97074 Würzburg

The topologically non-trivial insulators realized in HgTe quantum wells (QWs) have recently attracted considerable attention because of their unique property: the existence of the gap in the bulk and the gapless edge states on the sample boundaries. Depending on the width of the HgTe QW the structure can be a trivial insulator with normal band structure when the QW width is smaller than 6.3 nm, or a topologically non-trivial insulator with inverted band structure for thicker QWs. Here we show that it is possible to distinguish the topologically trivial from non-trivial insulator states on the basis of bulk transport properties only. Using the effective four-band model [1], we have calculated the bulk conductance through the two-dimensional metal/HgTe insulator/metal structure. Whereas for the trivial insulator the conductance increases monotonically with decreasing distance between the electron reservoirs L, a non-monotonic behaviour of the bulk transport depending on L has been found for the insulator in the inverted regime. Interestingly, the bulk transport contribution can even exceed the quantized conductance caused by edge state transport and should be taken into account for the interpretation of future experiments.

[1] B. A. Bernevig et al., Science, 314, 1757 (2006).