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arXiv · 1604.05846

Quantization of Conductance Minimum and Index Theorem

Satoshi Ikegaya·Shu-Ichiro Suzuki·Yukio Tanaka·Yasuhiro Asano
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Abstract

We discuss the minimum value of the zero-bias differential conductance $G_{\textrm{min}}$ in a junction consisting of a normal metal and a nodal superconductor preserving time-reversal symmetry. Using the quasiclassical Green function method, we show that $G_{\textrm{min}}$ is quantized at $ (4e^2/h) N_{\mathrm{ZES}}$ in the limit of strong impurity scatterings in the normal metal. The integer $N_{\mathrm{ZES}}$ represents the number of perfect transmission channels through the junction. An analysis of the chiral symmetry of the Hamiltonian indicates that $N_{\mathrm{ZES}}$ corresponds to the Atiyah-Singer index in mathematics.

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Satoshi Ikegaya, Shu-Ichiro Suzuki, Yukio Tanaka, Yasuhiro Asano. 2016-04-20. Quantization of Conductance Minimum and Index Theorem. https://doi.org/10.1103/physrevb.94.054512

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