Coupling Lattice Instabilities Across the Interface in Ultrathin Oxide Heterostructures

Abstract

Oxide heterointerfaces constitute a rich platform for realizing novel functionalities in condensed matter. A key aspect is the strong link between structural and electronic properties, which can be modified by interfacing materials with distinct lattice symmetries. Here we determine the effect of the cubic-tetragonal distortion of SrTiO 3 on the electronic properties of thin films of SrIrO 3 , a topological crystalline metal hosting a delicate interplay between spin-orbit coupling and electronic correlations. We demonstrate that below the transition temperature at 105 K, SrIrO 3 orthorhombic domains couple directly to tetragonal domains in SrTiO 3 . This forces the inphase rotational axis to lie in-plane and creates a binary domain structure in the SrIrO 3 film. The close proximity to the metal-insulator transition in ultrathin SrIrO 3 causes the individual domains to have strongly anisotropic transport properties, driven by a reduction of bandwidth along the in-phase axis. The strong structure-property relationships in perovskites make these compounds particularly suitable for static and dynamic coupling at interfaces, providing a promising route towards realizing novel functionalities in oxide heterostructures.Engineering matter with tailored properties is one of the main objectives in materials science. Perovskite oxides have been at the center of attention due to the combination of a flexible lattice structure and strong structure-property relationships. At heterointerfaces, structural phases and domain patterns that are not present in bulk can manifest. 1-3 Such artificial phases can have a marked effect on electronic and magnetic properties and have been shown to modify features such as magnetic anisotropy, 4,5 interfacial ferromagnetism 6-8 and ferroelectricity. 9 Recent years have seen an increasing amount of attention focused on the exploration of nanoscale domains, which have emerged as an abundant source of novel physical properties. [10][11][12][13][14] Control of such domain patterns however, remains an open challenge. A possible way forward is to incorporate materials that undergo structural phase transitions. A canonical example is SrTiO 3 , a widely used material that undergoes a transition from a cubic to a tetragonal phase when lowering the temperature below 105 K. At this temperature, SrTiO 3 breaks up into ferroelastic domains in which TiO 6 octahedra rotate about one of three possible directions. 15 When SrTiO 3 is used as a substrate for heteroepitaxial growth, the rotational distortion and resulting domain pattern can interact with the thin film due to octahedral connectivity across the interface. 16 In this context, semimetal SrIrO 3 is of particular interest, since dimensionality and octahedral rotations have been shown to be pivotal in the delicate interplay between spin-orbit coupling (SOC) and electronic correlations. [17][18][19]

Perovskite oxide heterojunction for Rashba-Dresselhaus assisted antiferromagnetic spintronics

“…Our estimated effective masses belong to similar ballpark range as reported by Manca et al [35] for the Ir-5d bands in SIO|STO heterostructure, although with a different tilt pattern of the IrO 6 octahedra. Further, anisotropic transport properties were reported in untrathin SIO|STO heterostructure, in agreement with our model of anisotropic effective mass [36].…”

Cu2O/CuS Nanocomposites Show Excellent Selectivity and Stability for Formate Generation via Electrochemical Reduction of Carbon Dioxide

“…Furthermore, we believe the presence of CuS is responsible for the improved electrochemical stability of Cu 2 O in the Cu 2 O/CuS nanocomposites under CO 2 RR conditions. According to previous studies, − a gradient band structure is expected to form at the heterojunction of CuS and Cu 2 O, promoting the photo-excited electron transfer from Cu 2 O to CuS and, thus, protecting Cu 2 O from reduction. Our characterization results, calculations, and long-term stability data provide indirect evidence to support this mechanism.…”

Non-universal current flow near the metal-insulator transition in an oxide interface

“…Through interface engineering, the domain patterns of the substrate can be imprinted onto the structure of thin films. Coupling between carriers in thin films and the structural properties or phonon modes of their substrates have been reported in a variety of heterostructures [42][43][44][45] . Thus, engineering these couplings can generally lead to nanoscale control over the electronic properties and critical behavior of the films.…”