Enhanced, homogeneously type-II superconductivity in Cu-intercalated PdTe₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• The type-II Dirac semimetal PdTe2 exhibits complex superconducting and magnetic properties.
• Previous studies indicated a mixed superconducting phase (type-I and type-II coexistence) in PdTe2, alongside vortex formation in magnetic fields.
• Scanning tunneling spectroscopy (STS) experiments revealed this mixed phase, prompting further investigation into its nature.

Purpose of the Study:

• To investigate the effect of copper (Cu) intercalation on the superconducting phase of PdTe2.
• To determine if Cu intercalation can influence the coexistence of type-I and type-II superconducting behaviors.
• To understand the underlying mechanisms responsible for changes in the superconducting phase.

Main Methods:

• Performed temperature and magnetic field-dependent scanning tunneling spectroscopy (STS) experiments.
• Utilized Cu-intercalated PdTe2 samples to probe changes in superconducting properties.
• Analyzed the evolution of the superconducting phase with varying temperature and magnetic field conditions.

Main Results:

• Cu intercalation increased the critical temperature (Tc) of the superconducting phase in PdTe2 from 1.7 K to 2.4 K.
• The mixed superconducting phase, characterized by type-I and type-II behavior coexistence, was suppressed by Cu intercalation.
• The system transitioned to a homogeneously type-II superconducting phase after Cu intercalation.

Conclusions:

• Cu intercalation effectively eliminates the mixed superconducting phase in PdTe2, leading to a homogeneous type-II phase.
• The observed changes are attributed to quasiparticle exchange mediated by Cu atoms and reduced coherence length due to increased disorder.
• This study offers a method to tune the superconducting phase and magnetic properties of Dirac semimetals like PdTe2.