On the structure of quantum intermediate state in type I superconductors

TL;DR

This paper analyzes the quantum intermediate state in high purity type I superconductors, revealing shorter structure periods and different dependencies on magnetic field and temperature compared to classical states, supported by experimental data.

Contribution

It introduces a theoretical model for the quantum intermediate state structure, highlighting differences from classical states and correlating with experimental findings in Gallium.

Findings

Quantum intermediate state has shorter period than classical

Structure period depends differently on magnetic field and temperature

Transition from classical to quantum state occurs near T~1K

Abstract

The calculation of spatial structure of a quantum intermediate state in high pure type I superconductors in external magnetic field at low temperatures is completed. The theoretical model of thermodynamics of intermediate state in type I superconductors was proposed by Andreev. It is shown, that in the quantum case, the period of structure of quantum intermediate state appears to be significantly shorter and it has different dependences on the magnetic field H and temperature T in comparison with the classical intermediate Landau state. The decrease of thickness of normal layers results in the increase of characteristic distance between the quantum Andreev levels of electronic excitations, and leads to the transition to the quantum intermediate state from the classical intermediate Landau state, which is realized at the higher temperatures T~1K. The comparison of the computed data with the experimental results in the researched case of high pure Gallium single crystal is made.