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arXiv · 2504.04123

Electron density and compressibility in the Kitaev model with a spatially modulated Phase in the superconducting pairing

Fabian G. Medina Cuy·Fabrizio Dolcini
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Abstract

A current flowing through a one-dimensional Kitaev chain induces a spatial modulation in its superconducting pairing, characterized by a wave vector $Q$, which is known to induce two types of topological phase transitions: one is the customary band topology transition between gapped phases, while the other is a Lifshitz transition related to the Fermi surface topology and leading to a gapless superconducting phase. We investigate the behavior of the electron density $ρ$ and the compressibility $κ$ across the two types of transitions, as a function of the model parameters. We find that the behavior of $ρ$ as a function of $Q$ and chemical potential $μ$ enables one to infer the ground state phase diagram. Moreover, the analysis of the compressibility $κ$ as a function of $μ$ enables one to distinguish the two transitions: While $κ$ exhibits a symmetric divergence across the band topology transition, it displays an asymmetric jump across the Lifshitz transition.

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Fabian G. Medina Cuy, Fabrizio Dolcini. 2025-04-05. Electron density and compressibility in the Kitaev model with a spatially modulated Phase in the superconducting pairing. https://doi.org/10.3390/condmat10010014

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