Spin–orbit engineering of thermoelectric and electronic properties in stanene

Two-dimensional stanene has emerged as a promising material for room-temperature thermoelectric applications and for exploring topological phenomena due to its strong intrinsic spin–orbit coupling. In this work, we develop an extended Kane–Mele tight-binding model for buckled stanene that includes higher-order hopping, finite orbital overlap due to lattice buckling, intrinsic spin–orbit coupling, and the Zeeman interaction from a perpendicular magnetic field. Using the Matsubara Green’s-function formalism and linear-response theory, we systematically investigate the electronic density of states, specific heat, electrical and thermal conductivities, Seebeck coefficient, and frequency-dependent optical absorption. Our results reveal a tunable competition between spin–orbit-induced gap opening and Zeeman-driven band shifting. Increasing spin–orbit coupling significantly enhances the low-temperature Seebeck coefficient, while a perpendicular magnetic field strengthens the electrical conductivity. Doping breaks particle–hole symmetry and optimizes the electronic power factor (and thereby the electronic contribution to the figure of merit) over a wide temperature range. The optical absorption spectra remain robust against moderate temperature variations but exhibit magnetically tunable interband peaks. This unified microscopic framework provides a consistent description of thermodynamic, transport, and optical properties in stanene and offers theoretical guidance for exploring the potential of tin-based two-dimensional materials in spintronic and thermoelectric applications.