Investigating the high-temperature thermoelectric properties of n -type rutile TiO 2

S. Thébaud (1) , Ch. Adessi (1) , G. Bouzerar (1)

1 UCBL - Université Claude Bernard Lyon 1

metal oxides are considered promising thermoelectric materials for harvesting hightemperature waste heat due to their chemical and thermal stability, abundance and low toxicity. Despite their typically strong ionic character, they can exhibit surprisingly high power factors σS 2 , as in n-type SrTiO3 for instance. Thus, it is worth examining other transition metal oxides that might equal or even surpass the performances of strontium titanate. This theoretical paper investigates the thermoelectric properties of n-type rutile TiO2, which is the most stable phase of titanium oxide up to 2000 K. The electronic structure is obtained through density functional theory calculations, while the prominent features of strong electron-phonon interaction and defects states are modelled using a small number of parameters. The thermoelectric transport properties are computed by solving the Boltzmann transport equation with the relaxation time approximation. The theoretical results are compared with a wealth of experimental data from the literature, yielding very good agreements over a wide range of carrier concentrations. This validates the hypothesis of band conduction in rutile TiO2 and allows the prediction of the high-temperature thermoelectric properties.

Domaines: Matière Condensée [cond-mat]

S. Thébaud, Ch. Adessi, G. Bouzerar. Investigating the high-temperature thermoelectric properties of n -type rutile TiO 2. Physical Review B, 2019, 100 (19), ⟨10.1103/PhysRevB.100.195202⟩. ⟨hal-03011397⟩