Thermoelectric transport in two-terminal topological nodal-line semimetals nanowires

Abstract

Recently discovered topological nodal-line semimetals (TNLSMs) have received considerable research interest due to their rich physical properties and potential applications. TNLSMs have the particular band structure to lead to many novel properties. Here we theoretically study the thermoelectric transport of a two-terminal pristine TNLSM nanowires and TNLSMs p–n–p junctions. The Seebeck coefficients S c and the thermoelectrical figure of merit ZT are calculated based on the Landauer-Büttiker formula combined with the nonequilibrium Green’s function method. In pristine TNLSM nanowires, we discuss the effect of the magnetic fields φ, the disorder D, the on-site energy µ z , and the mass term m on the thermoelectric coefficient and find that the transport gap can lead to a large S c and ZT. When transmission coefficient jumps from one integer plateau to another, S c and ZT show a series of peaks. The peaks of S c and ZT are determined by the jump of the transmission coefficient plateau and are not associated with the plateau itself. For TNLSMs p–n–p junctions, S c and ZT strongly depend on the parameter ξ of potential well. We can get a large ZT by adjusting the parameter ξ and magnetic field φ. In TNLSMs p–n–p junctions, ZT has the large value and is easily regulated. This setup has promising application prospects as a thermoelectric device.