Quantum oscillations, thermoelectric coefficients and the Fermi surface of semi-metallic WTe2
Abstract
We present a study of angle-resolved quantum oscillations of electric and thermoelectric transport coefficients in semi-metallic WTe2, which has the particularity of displaying a large B2 magneto-resistance. The Fermi surface consists of two pairs of electron-like and hole-like pockets of equal volumes in a "Russian doll" structure. Carrier density, Fermi energy, mobility and the mean-free-path of the system are quantified. An additional frequency is observed above a threshold field and attributed to magnetic breakdown across two orbits. In contrast to all other dilute metals, the Nernst signal remains linear in magnetic field even in the high-field (ωcτ 1) regime. Surprisingly, none of the pockets extend across the c-axis of the first Brillouin zone, making the system a three-dimensional metal with moderate anisotropy in Fermi velocity yet a large anisotropy in mean-free-path.