Suppression of Superconductivity in Heavy-ion Irradiated 2H-NbSe2 Caused by Negative Pressure

TL;DR

This study investigates how heavy-ion irradiation creates defects in 2H-NbSe2 crystals, leading to a suppression of superconductivity primarily due to lattice expansion acting as negative pressure, rather than disorder.

Contribution

It quantitatively separates the effects of lattice expansion and disorder on Tc suppression, highlighting the dominant role of negative pressure.

Findings

Tc decreases linearly with irradiation dose

Lattice parameters expand with irradiation, indicating negative pressure

Tc suppression is mainly due to lattice expansion, not disorder

Abstract

Effects of columnar defects created by 320 MeV Au irradiation on 2H-NbSe2 single crystals with a dose equivalent matching field up to 16 T were studied. Critical temperature is found to be suppressed almost linearly at a rate of 0.07 K/T. At the same time, the lattice parameters a and c are found to be expanded at rates of 0.016%/T and 0.030%/T, respectively. Such a lattice expansion should work as negative pressure to affect Tc. By separating the effect of heavy-ion irradiation on Tc suppression through lattice expansion and disorder, it is found that Tc is suppressed more by lattice expansion rather than by disorder.