Quantum Effects Boost Room-Temperature Thermoelectricity in Weyl Semimetals

Researchers at the Zernike Institute for Advanced Materials, University of Groningen report room-temperature thermoelectric responses in the low-symmetry type-II Weyl semimetals WTe₂ and TaIrTe₄ without requiring magnetic fields or magnetic materials. Exploiting harmonic detection with gradient-reversal techniques, the team resolved all symmetry-allowed components of the second-order thermoelectric tensor, including the nonlinear Seebeck, nonlinear Nernst, and nonlinear mixed-directional thermoelectric effects. The work demonstrates that both Berry-curvature-related and scattering-induced contributions govern these nonlinear thermoelectric responses, revealing a nuanced interplay of quantum mechanical phenomena. These results show that nonlinear thermoelectricity arises intrinsically from reduced crystal symmetry, offering a versatile platform for heat-to-charge current conversion beyond linear responses. A surprising discovery reveals that certain materials exhibit robust thermoelectric responses at ambient temperatures without relying on external magnetic fields. Recent work…