Electronic structure engineering the layered Dirac materials ZrTe₅ and HfTe₅ via Te point defects

Dirac materials have attracted substantial attention for applications in sensing and microelectronics. In recent years, they have also been found to offer a testbed for probing fundamental and cosmological physics, such as the detection of quantum anomalies and light dark matter, in experimentally tractable tabletop experiments.

In particular, the layered Dirac materials ZrTe₅ and HfTe₅ are widely celebrated for their highly strain-tunable electronic, topological, and transport properties. Many experimental efforts have reported anomalous transport properties that suggest these materials host a chiral anomaly. However, these transport properties are highly sample-dependent and correlate strongly with sub-stoichiometric Te content. Here we perform comprehensive ab initio density functional theory (DFT) calculations to shed light on the role Te point defects play in modulating the electronic structure of ZrTe₅ and HfTe₅. We probe Te point defects as an effective source of strain, in the form of chemical pressure; from these calculations we disentangle the coexisting effects of strain and chemical doping on the electronic structure. Our results offer a microscopic description of the mechanism driving the anomalous transport properties of ZrTe₅ and HfTe₅ with implications both for probes of cosmological physics as well as electronic structure engineering for next-generation microelectronics [1].

[1] E. A. Peterson, J.-X. Zhu, Adv. Phys. Res., 2300111 (2024) DOI: 10.1002/apxr.202300111