Pressure-induced Lifshitz transition in the type-II Weyl semimetal WP2

We report evidences of a pressure-induced Lifshitz transition in the type-II Weyl semimetal WP2 via resistance, synchrotron X-ray diffraction, and Raman scattering measurements with the aid of density functional theory calculations up to 50 GPa. The resistance at 2 K and 300 K and residual resistance ratio rise precipitously at ca. 20 GPa. The pristine orthorhombic structure is robust against pressures up to 50 GPa. There occurs a discontinuity in the unit cell volume, lattice parameter, lattice parameter ratio and axial compressibility at ～20 GPa. Two Raman-active modes soften abruptly accompanied with appearance of a new Raman-active mode at ～15 GPa. Density functional theory calculations identify drastic changes in the Fermi surface topology at～30 GPa. Our findings stimulate further pursuit of pressure-induced superconductivity via a Lifshitz transition in WP2.