Visualization by scanning SQUID microscopy of the intermediate state in the superconducting Dirac semimetal PdTe${}_2$

TL;DR

This study uses scanning SQUID microscopy to visualize the intermediate state in the superconducting Dirac semimetal PdTe${}_2$, revealing flux structures and domain wall properties characteristic of type-I superconductivity.

Contribution

First direct visualization of flux structures in PdTe${}_2$'s intermediate state, demonstrating its type-I superconductivity through advanced microscopy techniques.

Findings

Flux structures are history-dependent and change shape with magnetic field.

Presence of Landau branching indicated by surface field measurements.

Determined the domain wall width in the intermediate state.

Abstract

The Dirac semimetal PdTe${}_2$ becomes superconducting at a temperature $T_{c}=1.6$~K. Thermodynamic and muon spin rotation experiments support type-I superconductivity, which is unusual for a binary compound. A key property of a type-I superconductor is the intermediate state which presents a coexistence of superconducting and normal domains (flux structures) at magnetic fields lower than the thermodynamic critical field $H_{c}$. By means of scanning SQUID microscopy (SSM) we observe flux structures in the superconducting state of PdTe${}_2$. The flux structures are strongly history dependent with a transition from round shapes to laminar shapes as the magnetic field is more and more increased. The field amplitudes measured at the surface are indicative for the presence of Landau branching. The domain wall width in the intermediate state has been determined.