Effect of Two‐Dimensional Crystal Orbitals on Fermi Surfaces and Electron Transport in Three‐Dimensional Perovskite Oxides

Abstract

Perovskite oxides are candidate materials in catalysis, fuel cells, thermoelectrics, and electronics, where electronic transport is vital to their use. While the fundamental transport properties of these materials have been heavily studied, there are still key features that are not well understood, including the temperature‐squared behavior of their resistivities. Standard transport models fail to account for this atypical property because Fermi surfaces of many perovskite oxides are low‐dimensional and distinct from traditional semiconductors. In this work, the low‐dimensional Fermi surfaces of perovskite oxides are chemically interpreted in terms of two‐dimensional crystal orbitals that form the conduction bands. Using SrTiO3 as a case study, the d/p‐hybridization that creates these low‐dimensional electronic structures is reviewed and connected to its fundamentally different electronic properties. A low‐dimensional band model explains several experimental transport properties, including the temperature and carrier‐density dependence of the effective mass, the carrier‐density dependence of scattering, and the temperature dependence of resistivity. This work highlights how chemical bonding influences semiconductor transport.

Machine Learning Chemical Guidelines for Engineering Electronic Structures in Half-Heusler Thermoelectric Materials

“…The band structure has a flat and dispersive character between the Xand W-points, which is similar to the band character found in SrTiO 3 and some full-Heusler phases [33,34]. There may be differences in transport properties between materials doped on each of the three sites.…”

Electron–Phonon Coupling and Electron–Phonon Scattering in SrVO3

“…Bi [14] ) leads to 1/τ ≈ ρ(T) ≈ T 2 in some temperature range. As recently emphasized by Snyder et al, [53,54] the topological 2D feature of the FS in some metallic oxides, can be at the origin of 1/τ ≈ ρ(T) ≈ T 2 . [53,54] Indeed, a cylindrical Fermi surface of SVO has been observed by ARPES.…”

“…As recently emphasized by Snyder et al., the topological 2D feature of the FS in some metallic oxides can be at the origin of 1/ τ ≈ ρ ( T ) ≈ T 2 . [ 53 , 54 ] Indeed, a cylindrical FS of SVO has been observed by ARPES. [ 43 , 55 , 56 , 57 ] The recent observation of a similar T 2 ‐dependent resistivity in Bi 2 O 2 Se oxyselenides, where the FS is an elongated ellipsoid, [ 12 ] may point to a common origin.…”

Conduction band engineering of half-Heusler thermoelectrics using orbital chemistry

“…There is a flat band between CBM-X 3 (contributed by the d orbital of the Y atom) and Γ point (Δ E = 0.03 eV), with the CBM-X 2 (contributed by the d orbital of the X atom) close in energy (Δ E = 0.25 eV), which should have a complex Fermi surface with a high band degeneracy. 42,43 The orbital diversity of conduction band edges indicates that larger degeneracy can be achieved by engineering the energy offset.…”