Effect of pressure on the superconducting transition temperature of doped and neutron-damaged MgB2

TL;DR

This study investigates how pressure affects the superconducting transition temperature (T_c) of MgB2 samples doped with Al or C, or damaged by neutrons, revealing systematic changes linked to phonon spectrum alterations.

Contribution

It provides new insights into the pressure dependence of T_c in MgB2 with different modifications, emphasizing phonon spectrum changes as a key factor.

Findings

dT_c/dP values vary systematically with ambient T_c

Pressure derivatives evolve predictably with doping and damage

Phonon spectrum changes dominate T_c pressure dependence

Abstract

Measurements of the superconducting transition temperatures for Al-doped, C-doped and neutron-damaged-annealed MgB2 samples under pressure up to ~8 kbar are presented. The dT_c/dP values change systematically with the decrease of the ambient pressure T_c in a regular fashion. The evolution of the pressure derivatives can be understood assuming that the change in phonon spectrum is a dominant contribution to dT_c/dP.