Perspective: n-type oxide thermoelectrics via visual search strategies

Abstract

We discuss and present search strategies for finding new thermoelectric compositions based on first principles electronic structure and transport calculations. We illustrate them by application to a search for potential n-type oxide thermoelectric materials. This includes a screen based on visualization of electronic energy isosurfaces. We report compounds that show potential as thermoelectric materials along with detailed properties, including SrTiO3, which is a known thermoelectric, and appropriately doped KNbO3 and rutile TiO2.

Inducing n - and p -Type Thermoelectricity in Oxide Superlattices by Strain Tuning of Orbital-Selective Transport Resonances

“…Transition metal oxides are attractive for thermoelectric applications owing to their chemical and thermal stability and environmental friendliness as well as to the prominent role of electronic correlations. 1,2 Considerable experimental and computational 3 research aims at finding oxide thermoelectrics with improved performance, mostly among bulk materials by doping [4][5][6][7] or strain. 8 An alternative strategy is to exploit heterostructuring and dimensional confinement.…”

Thermoelectric properties of n-type SrTiO3

“…Specifically, the surfaces in the 0.15 eV case consist of intersecting cylinders joined at the center around Γ and two small sections inside the center, as was discussed previously for STO and other d 0 cubic perovskites. 59 This low-dimensional-like intersecting cylinders in higher carrier concentration (right panel of Fig. 3) that originated from the t 2g orbitals is beneficial for achieving high ZT.…”

“…57,58 Within a simple parabolic band model, the S(T) is proportional to effective mass (m * ) and decreases as the 2/3 power of doping concentration. Moreover, m * plays different roles in σ and S. For thermoelectric performance it is important to have both high S and high σ, which as discussed previously 59 have opposite dependences on both carrier concentration and effective mass. This conundrum can be resolved by certain complex band structures that exploit the different transport integrals that enter σ and S. [60][61][62][63][64][65][66] STO has a particular band shape arising from the degeneracy of the t 2g levels in an octahedral crystal field that gives effectively lower dimensional behaviour in transport even though the material is cubic, analogous to the case of PbTe.…”

Research Update: Oxide thermoelectrics: Beyond the conventional design rules

“…A recent good review on this issue is recommended to the readers. 23 We wish to also note that we do not discuss the lattice thermal conductivity mainly because of the page limitation. Another reason is that the strategies on how to reduce the lattice thermal conductivity, e.g., rattling 24 and nano-structuring, 25 are essentially applicable to oxides as well as other materials.…”