Anomalous temperature dependence of elastic constant c44 in V, Nb, Ta, Pd, and Pt

The anomalous temperature dependence of elastic constant c₄₄ for elements V, Nb, Ta, Pd, and Pt, has been calculated using first-principles theory. It is shown that the variation of elastic constant for simple elements can be approximated as the sum of thermal expansion and electronic components. The thermal expansion contributes the normal linearly decreasing effect to the elastic constant with temperature, while electronic contribution is determined by the unique character of electronic structure of elements and leads to the anomalous effect to the elastic constant with temperature.