Intrinsically low lattice thermal conductivity and thermoelectric performance of 2D Cu<sub>2</sub>Te
Emre Bölen, E. Deligöz, H Ozisik
Abstract
Abstract In this study, we employed density functional theory to investigate the structural, mechanical, dynamical, electronic, and thermal transport properties of 2D Cu 2 Te in the hexagonal P6/mm structure. Our results demonstrate that this structure is both mechanically and dynamically stable, and has a direct band gap, indicating its potential as a semiconductor. The high Grüneisen parameter value of 2D Cu 2 Te resulted in a lower lattice thermal conductivity compared to its bulk counterpart due to increased phonon scattering in the 2D structure. Furthermore, we observed that the Seebeck coefficient in 2D Cu 2 Te is higher in the p-type region, while the electrical conductivity is higher in the n-type region at lower temperatures. Two different approaches were used to calculate the lattice thermal conductivity, and it was found that the thermal conductivity decreases with dimension reduction in Cu 2 Te. Additionally, ultralow thermal conductivity was observed. Moreover, the lattice thermal conductivity plays a dominant role in the thermoelectric performance. The maximum ZT value for 2D Cu 2 Te was obtained as 1.28 at 700 K. Overall, our results suggest that 2D Cu 2 Te is a potential new candidate for high thermoelectric performance.