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Theory of tunneling spectroscopy for chiral topological superconductors
We study the charge conductance of an interface between a normal metal and a
superconducting quantum anomalous Hall system, based on the recursive Green's
function. The angle resolved conductance gamma(ky, eV) with the momentum ky
parallel to the interface and the bias voltage V shows a rich structure
depending on the Chern number N of the system. We find that when the bias
voltage is tuned to the energy dispersion of the edge mode, eV = Eedge(ky), the
angle resolved conductance gamma(ky,Eedge(ky)) shows a pronounced even-odd
effect; the conductance vanishes for N = 0 or 2 while it takes a universal
value 2e^2/h for N = 1. In particular, in N = 2 phase, we find that the
conductance gamma(ky,Eedge(ky)) becomes zero due to interference of two
degenerate Majorana edge modes, although the corresponding surface spectral
weight remains non-zero.Comment: 10 pages, 10 figure
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