Large magnetoresistance of a compensated metal Cu 2 Sb correlated with its Fermi surface topology

We report electrical transport properties and electronic structure of a nonmagnetic metal ${\mathrm{Cu}}_{2}\mathrm{Sb}$ single crystal. ${\mathrm{Cu}}_{2}\mathrm{Sb}$ was found to be a compensated metal with high carrier density $\ensuremath{\sim}{10}^{22}\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}3}$ and high carrier mobility $\ensuremath{\ge}{10}^{3}\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}^{2}/\mathrm{Vs}$ for both electron and hole carriers. The current-in-plane magnetoresistance at 2 K and 9 T was 730%, while the current-perpendicular-to-plane magnetoresistance at 2 K and 9 T was 2700% without the saturation. Angle-resolved photoemission spectroscopy throughout the three-dimensional (3D) bulk Brillouin zone signified a quasi-two-dimensional (2D) electron pocket axially centered along the M-A line and a 3D hole pocket at the \ensuremath{\Gamma} point, in accordance with the electron-hole compensated nature. The presence of quasi-2D open Fermi surface, in line with the first-principles band-structure calculations, is likely responsible for the observed nonsaturating current-in-plane magnetoresistance. The present result lays the foundation for realizing large magnetoresistance via Fermiology engineering in compensated metals.