From semiconductors to superconductors: a simple model for pseudogaps

TL;DR

This paper models a 2D semiconductor with local attraction, revealing a transition from superconducting to insulating phases at zero doping and a crossover at finite doping, with calculations of critical temperatures.

Contribution

It introduces a simple model capturing the pseudogap phenomena and phase transitions in semiconductors with local attraction.

Findings

Direct superconductor-insulator transition at zero doping

Smooth crossover at finite doping

Calculated critical temperatures for phase transitions

Abstract

We consider a two dimensional semiconductor with a local attraction among the carriers. We study the ground state of this system as a function of the semiconductor gap. We find a direct transition from a superconducting to an insulating phase for no doping at a critical value, the single particle excitations being always gapped. For finite doping we find a smooth crossover. We calculate the critical temperature due to both the particle excitations and the Berezinkii-Kosterlitz-Thouless transition.