Self-consistent Bogoliubov de Gennes theory of the vortex lattice state in a two-dimensional strong type-II superconductor at high magnetic fields

TL;DR

This paper develops a self-consistent Bogoliubov de Gennes theory for the vortex lattice in 2D strong type-II superconductors at high magnetic fields, revealing a quantum mixed state with a Landau--Bloch band structure and connecting to experimental observations.

Contribution

It introduces a novel theoretical framework for the vortex lattice in 2D strong type-II superconductors at high fields, capturing quantum effects near Hc2.

Findings

Identification of a quantum mixed state with Landau--Bloch band structure

Crossover from quantum to semiclassical behavior with decreasing magnetic field

Application to topological insulator surface superconductor matching experimental data

Abstract

A self-consistent Bogoliubov deGennes theory of the vortex lattice state in a 2D strong type-II superconductor at high magnetic fields reveals a novel quantum mixed state around the semiclassical Hc2, characterized by a well-defined Landau--Bloch band structure in the quasi-particle spectrum and suppressed order-parameter amplitude, which sharply crossover into the well-known semiclassical (Helfand-Werthamer) results upon decreasing magnetic field. Application to the 2D superconducting state observed recently on the surface of the topological insulator Sb2Te3, accounts well for the experimental data, revealing a strong type-II superconductor, with unusually low carrier density and very small cyclotron mass, which can be realized only in the strong coupling superconductor limit.