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arXiv · 1804.06415

Zero-dimensional topologically nontrivial state in a superconducting quantum dot

Pasquale Marra·Alessandro Braggio·Roberta Citro
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Abstract

The classification of topological states of matter in terms of unitary symmetries and dimensionality predicts the existence of nontrivial topological states even in zero-dimensional systems, i.e., a system with a discrete energy spectrum. Here, we show that a quantum dot coupled with two superconducting leads can realize a nontrivial zero-dimensional topological superconductor with broken time-reversal symmetry, which corresponds to the finite size limit of the one-dimensional topological superconductor. Topological phase transitions corresponds to a change of the fermion parity, and to the presence of zero-energy modes and discontinuities in the current-phase relation at zero temperature. These fermion parity transitions therefore can be revealed by the current discontinuities or by a measure of the critical current at low temperatures.

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Pasquale Marra, Alessandro Braggio, Roberta Citro. 2018-06-08. Zero-dimensional topologically nontrivial state in a superconducting quantum dot. https://doi.org/10.3762/bjnano.9.162

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