2021/01/16 by Junaid Majeed Bhat, Abhishek Dhar, Bhat, Junaid Majeed +1 · 1 citation
Physics and Astronomy · #Quantum and electron transport phenomena #Topological Materials and Phenomena #Quantum many-body systems
paper · pdf · doi:10.48550/arxiv.2101.06376
We consider electron transport in a Kitaev chain connected at its two ends to\nnormal metallic leads kept at different temperatures and chemical potentials.\nTransport in this set-up is usually studied using two frameworks -- the\nnonequilibrium Green's function (NEGF) approach or the scattering approach. In\nthe NEGF approach the current and other steady state properties of a system are\nexpressed in terms of Green's functions that involve the wire properties and\nself-energy corrections arising from the leads. In the scattering approach,\ntransport is studied in terms of the scattering amplitudes of plane waves\nincident on the wire from the reservoirs. Here we show explicitly that these\ntwo approaches produce identical results for the conductance of the Kitaev\nchain. Further we show that the NEGF expression for conductance can be written\nin such a way that there is a one-to-one correspondence of the various terms in\nthe NEGF expression to the amplitudes for normal transmission, Andreev\ntransmission and Andreev reflection in the scattering approach. Thereby, we\nobtain closed form expressions for these. We obtain the wavefunctions of zero\nenergy Majorana bound states(MBS) of the wire connected to leads and prove that\nthey are present in the same parameter regime in which they occur for an\nisolated wire. These bound states give rise to perfect Andreev reflection\nresponsible for zero bias quantized conductance peak. We discuss the dependence\nof the width of this peak on different parameters of the Hamiltonian and relate\nit to the MBS wavefunction properties. We find that the peak broadens if the\nweight of the MBS in the reservoirs increases and vice versa.\n