Large out-of-plane and linear in-plane magnetoresistance in layered hafnium pentatelluride

The prediction of the quantum spin Hall effect in two-dimensional ZrTe5 and HfTe5 monolayers has generated considerable recent interest in these materials. In addition, Dirac points and chiral-anomaly-induced negative longitudinal magnetoresistance (MR) have been observed in ZrTe5. Herein, we study the transport behavior of HfTe5 single crystals in detail and find a large (0.9 x 10(4)%) out-of-plane transverse MR, which is among the highest for layered materials reported thus far. We also encounter a large linear in-plane transverse (magnetic field parallel to c, current parallel to a) MR and discuss its possible origin. The mass anisotropy (gamma = 5.4 at 125 K) obtained by scaling angle-dependent MR data is consistent with the HfTe5 elliptical Fermi surface