Superhigh thermoelectric figure of merit in silver halides AgCl and AgBr from first principles

Understand

Searching for the high-performance thermoelectric (TE) materials has always been a long-held dream in the thermoelectricity field.

• Recently, it is found in experiments that the largest figure of merit ZT of $2.6$ can be reached in SnSe crystals at 923 K and Cu2Se sample at 850 K, which arouses the enormous interest of seeking high-ZT materials.
• Based on first-principle calculations and Boltzman transport equation (BTE), we report in this letter that silver halides (AgCl and AgBr) in rocksalt structure have excellent TE performances.
• A superhigh ZT of about 7.0 at mid-temperature (~600K) is obtained in the p-type doped AgCl and AgBr crystals, which far exceeds the ZT values of all current bulk TE materials.