Topological Dirac states in a layered telluride TaPdTe5 with quasi-one-dimensional PdTe2 chains

We report the synthesis and systematic studies of a new layered ternary telluride TaPdTe5 with quasi-one-dimensional PdTe2 chains. This compound crystalizes in a layered orthorhombic structure with space group Cmcm. Analysis of its curved field-dependent Hall resistivity, using the two-band model, indicates the hole-dominated transport with a high mobility μh=2.38×103cm2V−1s−1 at low temperatures. The in-plane magnetoresistance (MR) displays significant anisotropy with field applied along the crystallographic b axis. The MR with the current applied along the c axis is also measured in high magnetic fields up to 51.7 T. Remarkably, it follows a power-law dependence and reaches (9.5×103)% at 2.1 K without any signature of saturation. The de Haas–van Alphen oscillations show a small Fermi surface pocket with a nontrivial Berry phase. The Shubnikov–de Haas (SdH) oscillations are detected at low temperatures and under magnetic fields above 28.5 T. Two effective masses m* (0.26me and 0.41me) are extracted from the oscillatory SdH data. Our first-principles calculations unveil a topological Dirac cone in its surface states, and, in particular, the topological index indicates that TaPdTe5 is a topologically nontrivial material.