Propagation Control of Octahedral Tilt in SrRuO₃ via Artificial Heterostructuring

Abstract

Bonding geometry engineering of metal–oxygen octahedra is a facile way of tailoring various functional properties of transition metal oxides. Several approaches, including epitaxial strain, thickness, and stoichiometry control, have been proposed to efficiently tune the rotation and tilt of the octahedra, but these approaches are inevitably accompanied by unnecessary structural modifications such as changes in thin‐film lattice parameters. In this study, a method to selectively engineer the octahedral bonding geometries is proposed, while maintaining other parameters that might implicitly influence the functional properties. A concept of octahedral tilt propagation engineering is developed using atomically designed SrRuO 3 /SrTiO 3 (SRO/STO) superlattices. In particular, the propagation of RuO 6 octahedral tilt within the SRO layers having identical thicknesses is systematically controlled by varying the thickness of adjacent STO layers. This leads to a substantial modification in the electromagnetic properties of the SRO layer, significantly enhancing the magnetic moment of Ru. This approach provides a method to selectively manipulate the bonding geometry of strongly correlated oxides, thereby enabling a better understanding and greater controllability of their functional properties.

Unconventional interlayer exchange coupling via chiral phonons in synthetic magnetic oxide heterostructures

“…Note that the out-ofplane M (T) shows the conventional FM behaviors of SRO with the same T c and without any downturn, consistent with previous studies (fig. S5) (21,(24)(25)(26)(27). Magnetic field (H)-dependent in-plane magnetization [M (H)] curves of the superlattices consistently support the AFM-like behavior, with a double hysteresis loop and a large coercive field of ~1.8 T appearing below ~80 K (Fig.…”

“…We deliberately grew oxide superlattices with alternating and -atomic unit cells (~0.4 nm) of SRO (t SRO ) and STO (t STO ), respectively, repeated for  times on STO (001) substrates, i.e., [|]  , using pulsed laser epitaxy (see Materials and Methods and figs. S1 to S3) (21,(24)(25)(26)(27). An intriguing oscillation in the in-plane magnetization is observed as a function of t STO , indicating the presence of an unconventional IEC across the NM-I spacer.…”

The Tunability of Oxygen Evolution Reaction in Flexible Van der Waals Manganite Membrane

“…As we have known that the stress of the complex oxide thin film releases within a very thin layer by the octahedra reconstruction, for instance, in La 1-x Sr x MO 3 or SrRuO 3 . [17][18][19] Thus, not surprisingly, the interfacial lattice mismatch can not drive to the surface ideally, however, OER activity is extraordinarily surface sensitive. Van der Waals heterostructures, such as mica-based ones, offer an excellent platform of flexible TMO membranes with continuous tunability of strain benefiting from the mechanical property of mica substrate, [20][21][22][23][24] and most importantly the strain release can be neglected.…”

Spin-orbit coupling driven orbital-selective doping effect in Sr2Ru1−xIrxO4

“…In heavy metal compounds such as 4d/5d transition metal oxides (TMOs), the strong SOC reconstructs the orbital eigenstates, which eventually results in unexpected novel phenomena such as metal-insulator transition [7][8][9][10] and topological semimetallic behavior [11]. The SOC strength in 4d/5d TMOs (150-400 meV) [9,12] is comparable with the energy scale of crystal field splitting (a few hundreds of meV) [13][14][15], and therefore SOC may trigger an orbital-selective behavior in the same way that the crystal structure does.…”

“…Until now, crystal structure was thought to be the most important factor to trigger orbitalselective phenomena. However, the energy scales of SOC strength (150-400 meV in 4d/5d TMOs) [9,12] are comparable with that of crystal field splitting (a few hundreds of meV) [13][14][15], and thus the SOC may be a factor that is sufficient to trigger orbital-selective phenomena. Consistent with this, we observe an orbital-selective doping effect in SRIO that is driven by SOC variation, thus our study may expand the boundary of orbital-selective physics to materials in the strong SOC regime.…”