Exploring the pressure and spin–orbit coupling effects in Pt3Sn2S2: a kagome-type analog of Co3Sn2S2

Abstract

We present a detailed theoretical study of Pt₃Sn₂S₂, a layered kagome-type material obtained by replacing Co with Pt in Co₃Sn₂S₂, a system extensively studied in Nat. Commun. (2020, 11, 3985) and Rev. Phys. (2022, 8, 100072), though the Pt-analog remains largely unexplored. Thermodynamic stability was confirmed via formation energy calculations, while mechanical stability was evaluated using the Voigt–Reuss–Hill (VRH) approximation and elastic stability conditions. Dynamical and thermal stability were validated through phonon dispersion and ab initio molecular dynamics simulations, with Pugh's criterion classifying the material as ductile. Spin–orbit coupling (SOC) induces band splitting, accompanied by a SOC-driven transition from non-relativistic band touching to relativistic band inversion. Under applied pressure, the coupling of spin and valley degrees of freedom generates spin-valley intertwined Dirac cones, enabling tunable electronic properties for spintronic and valleytronic applications. Furthermore, Boltzmann transport calculations using AMSET reveal a high Seebeck coefficient (80 μV K⁻¹ without SOC) at 300 K and low thermal conductivity, highlighting its potential for high-performance thermoelectric devices. Further impurity scattering (IMP) dominates at low temperatures (<200 K), and decreases with temperature, while polar optical phonon (POP) scattering becomes significant at higher temperatures, overtaking IMP near 250 K without spin–orbit coupling. With SOC, impurity scattering exhibits an anomalous increase with temperature, while POP is more active even at low temperatures. These findings establish Pt₃Sn₂S₂ as a promising material for applications spanning topological physics, thermoelectrics, and advanced electronic technologies.