Superconducting transition temperature Tsub(c) of lanthanum and actinium under high pressure and a new empirical relation for the volume dependence of Tsub(c)

The superconducting transition temperatures of lanthanum (La) and actinium (Ac) are calculated at various high pressures from the relativistic band-structure results obtained using the relativistic augmented plane-wave (RAPW) method. From the calculations it is seen that Tsub(c) increases with increasing pressure or decreasing cell volume for both the metals. A new empirical relation for the volume dependence of Tsub(c) is obtained. (author)