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arXiv · 1304.2782

Non-universal conductance in quasi-helical quantum wires

Tobias Meng·Daniel Loss
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Abstract

In a quantum wire with ideal helical modes, the conductance is quantized in units of e^2/h, provided the wire is connected to Fermi liquid leads. We show that this universality does not hold in partially gapped quasi-helical systems such as Rashba nanowires subject to a magnetic field, which are commonly used to mimic helical Luttinger liquids. Instead, their conductance takes a non-universal value that depends on the interactions in the wire, even in the presence of Fermi liquid leads. The non-universal conductance is rooted in a non-trivial mixing of spin and charge degrees of freedom, which in turn defines a non-helical low-energy Hamiltonian.

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Tobias Meng, Daniel Loss. 2013-08-19. Non-universal conductance in quasi-helical quantum wires. https://arxiv.org/abs/1304.2782

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