Achieving significant enhancement of thermoelectric power factor of hexagonal PdTe2 monolayer by using strain engineering

Hexagonal PdTe2, one of the two-dimensional transition metal dichalcogenies, has drawn substantial exploration as a potential thermoelectric material for low-temperature applications. However, how to further enhance its thermoelectric properties has still not been systematically investigated. In this paper, we research the electronic and thermoelectric properties of h-PdTe2 tuning by uniaxial and biaxial strains using first-principles calculations. The indirect bandgap of the unstrained h-PdTe2 is 0.195eV. It is found that both uniaxial and biaxial strains can reduce the bandgap and influence the Pd-d orbitals and Te-p orbitals near the Fermi level, leading a transition from semiconductor to conductor. It is worth noting that under biaxial strains, the power factor of h-PdTe2 is significantly improved. At the temperature of 300 K, the maximum power factors of n-type and p-type h-PdTe2 under strains of -4% and 2% are 97.56% and 61.26% higher than those without strain, respectively. Therefore, biaxial strains at low temperature can greatly enhance the thermoelectric properties of h-PdTe2. Our research not only offers a practical method for significantly enhancing the thermoelectric properties of 2D TMDs, but also promote its application in the field of thermoelectricity.