Unveiling the electronic structure of the charge density wave and topological semimetal TaTe4 through high-field magnetotransport measurements

Abstract: Understanding the interplay between topology and correlated electron states is central to the study of quantum materials. TaTe$_4$, a charge density wave (CDW) compound predicted to host topological phases, offers a platform to explore this interplay. Here, we report a comprehensive study of the Fermi surface (FS) of TaTe$_4$ via high-field magnetotransport measurements and density functional theory (DFT) calculations. Using three distinct field-current configurations, we resolve four out of five FS pockets predicted in the CDW phase, with no evidence of residual non-CDW features - in contrast to recent ARPES studies. Remarkably, we identify a previously unobserved quasi-cylindrical hole pocket and a high-frequency quantum oscillation contribution to the magnetoresistance attributable to magnetic breakdown between reconstructed FS sheets, from which we estimate a CDW gap of $\sim$0.29 eV. Additionally, we observe a robust linear magnetoresistance (MR) for all field orientations when current flows along the $a-$axis, with a distinct high-field linear MR regime emerging near the $c-$axis, consistent with FS hot spots and magnetic breakdown. Our results establish TaTe$_4$ as a paradigmatic system where CDW-driven FS reconstruction governs the bulk electronic structure, enabling new routes to probe the novel physics that can arise in the intersection between correlated electronic states and topological band features.