Spontaneous symmetry breaking at surfaces of d-wave superconductors: Influence of geometry and surface ruggedness
Artikel i vetenskaplig tidskrift, 2019

Surfaces of d-wave superconductors may host a substantial density of zero-energy Andreev states. The zero-energy flat band appears due to a topological constraint, but comes with a cost in free energy. We have recently found that an adjustment of the surface states can drive a phase transition into a phase with finite superflow that breaks time-reversal symmetry and translational symmetry along the surface. The associated Doppler shifts of Andreev states to finite energies lower the free energy. Direct experimental verification of such a phase is still technically difficult and controversial, however. To aid further experimental efforts, we use the quasiclassical theory of superconductivity to investigate how the realization and the observability of such a phase are influenced by sample geometry and surface ruggedness. Phase diagrams are produced for relevant geometric parameters. In particular, critical sizes and shapes are identified, providing quantitative guidelines for sample fabrication in the experimental hunt for symmetry-breaking phases.

thin superconducting films

andreev reflection

superconductivity

spontaneous symmetry breaking

Författare

Patric Holmvall

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

A. B. Vorontsov

Department of Physics, Montana State University

Mikael Fogelström

Chalmers, Mikroteknologi och nanovetenskap (MC2)

Tomas Löfwander

Chalmers, Mikroteknologi och nanovetenskap (MC2), Tillämpad kvantfysik

Physical Review B

24699950 (ISSN) 24699969 (eISSN)

Vol. 99 18 184511

Styrkeområden

Nanovetenskap och nanoteknik (2010-2017)

Infrastruktur

C3SE (Chalmers Centre for Computational Science and Engineering)

Ämneskategorier

Den kondenserade materiens fysik

DOI

10.1103/PhysRevB.99.184511

Mer information

Skapat

2019-05-28