Effect of pressure and composition on superconducting transition temperature of refractory high entropy alloys

Abstract Refractory high-entropy alloys have shown interesting superconductivity. Whereas the large degree of uncertainty from complicated chemical disorder makes the conventional ab initio calculations containing electron–phonon coupling very limited. In this work, two approaches based on McMillan-Allen-Dynes formula in combination with the virtual crystal approximation are used to study the superconducting transition temperature T c as a function of pressure and composition in Zr-Ta-Nb-Hf-X (X = Ti,V) refractory high-entropy alloys. With increase of pressure, the superconducting transition temperature has the dome shaped curve with the maximum of T c = 23.64 K for ZrTaNbHfTi and 23.40 K for ZrTaNbHfV at 125 GPa. When tuning chemical composition, we find that the increase of Nb enhances T c , while the increasing V and Ta reduce T c in ZrVTaNbHf. Our study is helpful for exploring new refractory high-entropy alloys with higher T c .