Direct Observation of Enhanced Lattice Stability inV3Si under Hydrostatic Pressure

The lattice transformation temperature $T_L$ of single-crystal ${\mathrm{V}}_3$Si was directly observed to decrease linearly with hydrostatic pressure at a rate of -(1.5 ± 0.1) × ${10}^{-4\mathrm{}}$ °K ${\mathrm{bar}}^{-1\mathrm{}}$. To explain the pressure dependence of $T_L$ and the elastic behavior, the Labbé-Friedel model must be extended to include interband charge-transfer effects as a new variable, in agreement with a recent calculation of Ting and Ganguly. We give a discussion of these results related to structural instability and superconductivity.