thin films via strategic doping*

Weyl and Dirac semimetals combine topological and semimetallic effects, making them candidates for interesting and effective thermoelectric transport properties. Previous work in the Weyl semimetal NbP demonstrated the simultaneous presence of both a large Nernst and magneto-Seebeck effect and how doping strongly alters both thermopowers [1]. The theory underlying transport in NbP is now applied to the Dirac semimetal Cd₃As₂ in order to predict the carrier concentrations at which the combined thermopowers are maximized under various temperature and field conditions. To achieve the very precise doping necessary for these predictions, thin films of Te-doped Cd₃As₂ were grown via molecular-beam epitaxy (MBE) at the predicted carrier density levels. The magneto-thermoelectric transport of these samples is characterized to determine the predictive power of the model and the viability of the MBE growth method for tuning the material to the specific operating conditions (i.e. temperature and magnetic field).

[1] E. F. Scott et al, Phys. Rev. B, 107, 115108 (2023).

This work is supported by the U.S. Department of Energy under award number DE-SC0020154 and the Office of Science Graduate Student Research (SCGSR) program under contract number DE-SC0014664.