Interplay of Long-Range Interactions, Helical Chains, and Lone Pairs in Tellurium

Abstract Tellurium (Te) has recently emerged as a promising thermoelectric material, exhibiting intrinsically low lattice thermal conductivity and high performance despite its elemental and structural simplicity. In this work, we employ first-principles calculations combined with Boltzmann transport theory to systematically study the thermoelectric property and performance of helical Te. Our analysis shows that lone electron pairs and the helical chain strongly enhance lattice anharmonicity and suppress phonon group velocities, yielding markedly reduced lattice thermal conductivity. Including Born effective charges introduces long-range corrections that strongly renormalize electrical transport and qualitatively reshape the dominant phonon modes governing electron–phonon scattering, leading to a ~31.0% reduction of the maximum zT in agreement with experiment. These results provide a microscopic understanding of Te’s anomalously low lattice thermal conductivity and anisotropic transport, and suggest design principles for high-performance thermoelectrics in helical-chain materials and electrides.