Nontrivial band topology coupled thermoelectrics in VSe2/MoSe2 van der Waals magnetic Weyl semimetal

Abstract

Abstract The correlation between topological and thermoelectrics promotes numerous interesting electronic phenomena and sets the stage for efficient thermopower devices. Herein, we report nontrivial band topology of 1T–VSe2/1H–MoSe2 van der Waals system and also probe its thermoelectric (TE) characteristics on the basis of first-principle calculations. The crossover of bands, which creates a close loop near Fermi level along M–K high symmetry points, gets inverted at former crossing points of bands, under spin–orbit coupling effect. The calculated Chern Number C = 1 supports the nontrivial band topology whereas the broken time reversal symmetry asserts its magnetic Weyl semimetallic behavior. The nontrivial band topology falls under the category of Type-I Weyl band crossing. We delve into the TE characteristics of the proposed topological material by employing constant relaxation time approximation. The heterostructure shows high electrical conductivity of order 106 S m−1 at both 300 K and 1200 K, and a low magnitude of Seebeck coefficient (S) value of 79.3 μV K−1 near room temperature. Such interplay between the topological phase and TE characteristics can lay foundation for next-generation topological-TE devices.