High-pressure induces topology boosting thermoelectric performance of Bi₂Te₃

Decoupling conductivity(σ)and Seebeck coefficient(S)by electronic topological transitions (ETT) under high pressure (2-4 GPa) is a promising method for bismuth telluride (Bi₂Te₃) to optimize thermoelectric (TE) performance. However, theScannot dramatically increase with increasingσwhen ETT occurs in Bi₂Te₃, which impedes optimizing TE performance by utilizing ETT in Bi₂Te₃. A new strategy of enhanced ETT by combining lattice distortions and high pressure is proposed in this work. The lattice distortions in Bi₂Te₃were introduced by high pressure and high temperature (HPHT) treatment to generate surplus dislocations. Thein-situmeasurements ofσandSat HPHT in Bi₂Te₃with lattice distortions show an enhanced ETT effect at 2 GPa, which causes decoupleσandSwith an anomalous increase in its|S|about 22%. The ETT effect causes the figure of merit (ZT) of Bi₂Te₃can be improved to 0.275 at 1.50-2.62 GPa, 460 K, it is more than 62% compared with 0.79 GPa, at 450 K. The excellent TE performance of Bi₂Te₃arising from the lattice distortions can result in local non-hydrostatic pressure which enhances ETT under high pressure. This work provides a new strategy to enhance ETT to decoupleσandS, and search for better TE materials from the pressure dimension in the future.