Speaker
Description
Transition-metal dichalcogenides exhibit a range of exploitable properties, including the chiral magnetic effect, orbital Hall effect (OHE), type-II Dirac cones that break the Lorentz invariance, and topologically non-trivial surface states. Understanding the nature of the charge carriers and the electronic structure of the Dirac semimetal $\text{PtSe}_2$, which offers both air-stability and spin-orbit coupling (SOC), is essential for advancing experimental realizations of OHE-based devices and clarifying the role of the Dirac cones. We present a comprehensive low-temperature and high-magnetic-field magnetotransport study of $\text{PtSe}_2$ flakes, focusing on the Shubnikov-de Haas (SdH) oscillations, which emerge as the applied magnetic field strength exceeds $4.5\,\text{T}$. These oscillations orbits are found to occur in-plane and emerge up to a layer thickness of $\sim 18\,\text{nm}$, with their amplitude increasing and frequency decreasing for thinner flakes. Moreover, Pt vacancies are found to play a crucial role for the carrier dynamics, as they contribute a magnetic moment at the flake surfaces, as corroborated by a density functional theory calculations. The Pt vacancies suppress the SOC and act as magnetic impurities, which gives rise to Kondo scattering. The findings provide quantitative insights into the charge carrier dynamics and illuminate the effect of Pt vacancies on the compound properties. This positions $\text{PtSe}_2$ as a platform for studying the OHE and provides crucial information for the design of prospective spintronic and orbitronic devices.