Tudor D. Stanescu, Roman M. Lutchyn, S. Das Sarma
We show that the topological Majorana quasiparticles hosted by semiconductor nanowires much longer than the superconducting coherence length are adiabatically connected with discrete zero-energy states generically occurring in short nanowires. We demonstrate that these zero-energy crossings can be tuned by an external magnetic field and are protected by the particle-hole symmetry. We study the evolution of the low-energy spectrum as a function of the magnetic field, wire length, and chemical potential, manifestly establishing that the low-energy physics of short wires is directly related to that occurring in long nanowires. In the presence of finite energy resolution, invariably operational under experimental conditions, the near-zero-energy states of a short wire give rise to a zero bias conductance peak over a finite magnetic field range.
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http://arxiv.org/abs/1208.4136
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