Physical insights into the ultralow lattice thermal conductivity and high thermoelectric performance of bulk LiMTe₂ (M = Al, Ga)

Abstract

Ternary chalcogenides are well known in the world of thermoelectric research, but most of them show noticeable efficiency for either their n-type or p-type cases. Herein, combining the results of...

Understanding the origin of the high thermoelectric figure of merit of Zintl-phase KCaBi

“…Improvement of ZT requires independent and simultaneous enhancement of the power factor (PF = S 2 s) and reduction of the thermal conductivity (k e + k l ), which is challenging due to the inverse and direct coupled interdependency of S, s, and k e . Large PF and optimized values of S and s can be obtained simultaneously due to the presence of converged dispersed and non-dispersed bands at the band edges of the electronic band structure, 1,2 high and steep density of states in the vicinity of the Fermi level, [3][4][5][6] etc., which may be present by default in some materials [7][8][9][10] due to their unusual structural properties or can be achieved by doping/substituting heavy elements, [11][12][13][14][15][16][17][18] nanostructuring, 19,20 application of pressure, 21 electric field, 22 and lattice strain, [23][24][25][26] and so on. Zintl-phase compounds have been extensively studied in recent years to demonstrate their applicability as thermoelectric materials with high thermoelectric performance caused by a high power factor and very low lattice thermal conductivity.…”