AB INITIO STUDY OF SUPERCONDUCTIVITY IN VANADIUM, NIOBIUM AND TANTALUM UNDER PRESSURE

Abstract

The superconducting transition temperature of group V- B metals Vanadium (V), Niobium (Nb) and Tantalum (Ta) under normal and high pressure are reported. The normal pressure superconducting transition temperature of hcp V, Nb and Ta agree well with the previous calculations. The high-pressure superconductivity exhibits significant deviations from the normal pressure due to s-d transitions. Under normal conditions the superconducting transition of Vanadium occurs at 5,95 K (Tc). When the pressure is increased it is predicted that Tc increases at a rate of 10.8 K/M bar for pressures up to 1.4 M bar, where as the experimental increases is 9.6 K/M bar for pressure up to 1.2 M bar. On further increase of pressure Tc begins to decrease at a rate of 1.4 K/M bar in bcc structure and 0.24 K/M bar in fcc structure. Similar calculations are carried out for Niobium and Tantalum.