Structural and electronic properties ofSrZrO3and Sr(Ti,Zr)O3alloys

Abstract

Using hybrid density functional calculations we study the electronic and structural properties of SrZrO3 and ordered Sr(Ti,Zr)O3 alloys. Calculations were performed for the ground-state orthorhombic (Pnma) and high-temperature cubic (Pm3m) phases of SrZrO3. The variation of the lattice parameters and band gaps with Ti addition was studied using ordered SrTixZr1−xO3 structures with x=0, 0.25, 0.5, 0.75, and 1. As Ti is added to SrZrO3, the lattice parameter is reduced and closely follows Vegard's law. On the other hand, the band gap shows a large bowing and is highly sensitive to the Ti distribution. For x=0.5, we find that arranging the Ti and Zr atoms into a 1×1 SrZrO3/SrTiO3 superlattice along the [001] direction leads to interesting properties, including a highly dispersive single band at the conduction band minimum (CBM), which is absent in both parent compounds, and a band gap close to that of pure SrTiO3. These features are explained by the splitting of the lowest three conduction-band states due to the reduced symmetry of the superlattice, lowering the band originating from the in-plane Ti 3dxy orbitals. The lifting of the t2g orbital degeneracy around the CBM suppresses scattering due to electron-phonon interactions. Our results demonstrate how short-period SrZrO3/SrTiO3 superlattices could be exploited to engineer the band structure and improve carrier mobility compared to bulk SrTiO3.

Homogeneous/Inhomogeneous‐Structured Dielectrics and their Energy‐Storage Performances

“…Dielectric materials such as strontium titanate (SrTiO 3 ), based on perovskite materials, have been widely used in electronic devices for integrated circuits . SrTiO 3 has several features that may prompt it to be suitable for high‐voltage applications, such as the stable valence states of cations and its nonferroelectric behavior, such that it cannot experience electromechanical failure mechanisms under high electrical fields.…”

Resistive switching in a LaMnO3 + δ/TiN memory cell investigated by operando hard X-ray photoelectron spectroscopy

“…Motivated by the growing interest in novel non-volatile resistive random-access memories (RRAMs), many new oxide-based heterostructures have emerged as potential candidates to build alternative memristive devices. Among the plethora of oxides exhibiting valence change mechanism, a number of perovskites, such as (Pr,Ca)MnO3, [1] SmNiO3, [2] SrZrO3, [3][4][5] LaSrMnO3, [6] as well as the thoroughly-studied SrTiO3 [7] have shown memristive behavior. Despite their promising functional properties (high speed, large ON/OFF ratio, large programming window, high endurance), fundamental knowledge and a thorough understanding of the RS mechanisms involved are in most cases still rather scarce.…”

Experimental verification of the ab initio phase transition sequence in SrZrO3 and comparisons with SrHfO3 and SrSnO 3

“…20,25 The dielectric dispersion and anomaly data suggest that there may be faint pseudo structural phase transition due to the significant tilting of ZrO 6 octahedra and screening among the electrons and the polaronic charge species. Due to the weakness of the dielectric anomaly, we checked the dielectric constant and tangent loss behavior for both …”