Magnetoresistance of semimetals: The case of antimony

Large unsaturated magnetoresistance has been recently reported in numerous semimetals. Many of them have a topologically nontrivial band dispersion, such as Weyl nodes or lines. Here, we show that elemental antimony displays the largest high-field magnetoresistance among all known semimetals. We present a detailed study of the angle-dependent magnetoresistance and use a semiclassical framework invoking an anisotropic mobility tensor to fit the data. A slight deviation from perfect compensation and a modest variation with magnetic field of the components of the mobility tensor are required to attain perfect fits at arbitrary strength and orientation of magnetic field in the entire temperature window of study. Our results demonstrate that large orbital magnetoresistance is an unavoidable consequence of low carrier concentration and the subquadratic magnetoresistance seen in many semimetals can be attributed to field-dependent mobility, expected whenever the disorder length scale exceeds the Fermi wavelength.