Singular angular magnetoresistance and sharp resonant features in a high-mobility metal with open orbits, ReO3

Abstract

We report high-resolution angular magnetoresistance (AMR) experiments performed on crystals of ReO3 with high mobility (>100000cm2/V s at 2 K) and extremely low residual resistivity (5–8 nΩcm). The Fermi surface, comprised of intersecting cylinders, supports open orbits. The resistivity ρxx in a magnetic field B=9 T displays a singular pattern of behavior. With E∥ˆx and B initially ∥ˆz, tilting B in the longitudinal kz−kx plane leads to a steep decrease in ρxx by a factor of 40. However, if B is tilted in the transverse ky−kz plane, ρxx increases steeply by a factor of 8. Using the Shockley-Chambers tube integral approach, we show that, in ReO3, the singular behavior results from the rapid conversion of closed to open orbits, resulting in opposite signs for AMR in orthogonal planes. The floor values of ρxx in both AMR scans are identified with specific sets of open and closed orbits. Also, the “completion angle” γc detected in the AMR is shown to be an intrinsic geometric feature that provides a new way to measure the Fermi radius kF. However, additional sharp resonant features that appear at very small tilt angles in the longitudinal AMR scans are not explained by the tube integral approach.