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arXiv · 1611.10356

Valley-Selective Landau-Zener Oscillations in Semi-Dirac p-n Junctions

K. Saha·R. Nandkishore·S. A. Parameswaran
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Abstract

We study transport across p-n junctions of gapped two-dimensional semi-Dirac materials: nodal semimetals whose energy bands disperse quadratically and linearly along distinct crystal axes. The resulting electronic properties --- relevant to materials such as TiO$_2$/VO$_2$ multilayers and $\alpha$-(BEDT-TTF)$_2$I$_3$ salts --- continuously interpolate between those of mono- and bi-layer graphene as a function of propagation angle. We demonstrate that tunneling across the junction depends on the orientation of the tunnel barrier relative to the crystalline axes, leading to strongly non-monotonic current-voltage characteristics, including negative differential conductance in some regimes. In multi-valley systems these features provide a natural route to engineering valley-selective transport.

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K. Saha, R. Nandkishore, S. A. Parameswaran. 2016-11-30. Valley-Selective Landau-Zener Oscillations in Semi-Dirac p-n Junctions. https://doi.org/10.1103/physrevb.96.045424

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