# Enhanced, homogeneous type II superconductivity in Cu-intercalated PdTe$_2$

## TL;DR

This study demonstrates that Cu-intercalation in PdTe$_2$ enhances its superconducting critical temperature and induces a transition from a mixed type-I/II phase to a homogeneous type-II phase, revealing new insights into its magnetic properties.

## Contribution

The paper provides experimental evidence that Cu-intercalation transforms PdTe$_2$ into a purely type-II superconductor by suppressing the mixed phase, highlighting the role of disorder and quasiparticle exchange.

## Key findings

- Critical temperature increases from 1.7 K to 2.4 K with Cu-intercalation.
- Mixed phase of type-I and type-II superconductivity disappears.
- System becomes homogeneously type-II superconducting.

## Abstract

Though the superconducting phase of the type-II Dirac semimetal PdTe$_2$ was shown to be conventional in nature, the phase continued to be interesting in terms of its magnetic properties. While certain experiments indicated an unexpected type-I superconducting phase, other experiments revealed formation of vortices under the application of magnetic fields. Recently, scanning tunneling spectroscopy (STS) experiments revealed the existence of a mixed phase where type-I and type-II behaviours coexist. Here, based on our temperature and magnetic field dependent STS experiments on Cu-intercalated PdTe$_2$ we show that as the critical temperature of the superconducting phase goes up from 1.7 K to 2.4 K on Cu-intercalation, the mixed phase disappears and the system becomes homogeneously type-II. This may be attributed to an averaging effect caused by quasiparticle exchange between type-I and type-II domains mediated by the Cu atoms and to decreased coherence length due to increased disorder.