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. •This paper proposes for the first time applied external strain tuning to improve the thermoelectric properties of h-PdTe2.•Based on first principles, the of h-PdTe2 have been systematically investigated under different strain tuning.•According to our research, h-PdTe2 is a high-performance TE material at low temperatures.•At the temperature of 300 K, the maximum power factor of n-type h-PdTe2 under -4% strain is 97.56% higher than without strain.•This paper provides a completely new perspective for improving the thermoelectric properties of 2D TMDs.