Effect of thermal fluctuations on the nontrivial topology of thed + idsuperconducting phase.

Abstract

The behavior of the topological index (TI), characterizing the properties of superconducting phases of quasi-two-dimensional systems with nontrivial topology, is investigated depending on the temperature and system parameters. For this purpose, a method of calculating the TI, based on a self-consistent functional-integral theory, is proposed. The chirald + idsuperconducting phase of a quasi-two-dimensional model with effective attraction between the electrons located at the nearest sites of a triangular lattice is considered. It is shown that the structure of the energy dependence of the self-energy function, which occurs when taking into account thermal fluctuations, does not lead to a change in the topological properties of the system. It is found that taking into account thermal fluctuations with an increase in the effective attraction between electrons expands the temperature range in which the value of the TI is close to the integerC1≃-2.