Abstract
Simultaneous control of structural and physical properties via applied electrical current poses a new, key research topic with both fundamental and technological significance. Studying the spin-orbit-coupled antiferromagnet Ca2RuO4, and its derivative with 3% Mn doping to alleviate the violent first-order transition at 357 K, we find that a small applied electrical current couples to the lattice by significantly reducing its orthorhombic distortions and octahedral rotations, while concurrently diminishing the 125-K antiferromagnetic transition. Further increasing electrical current density above 0.15A/cm2 induces a new nonequilibrium orbital state, with a transition signature at 80 K that features a simultaneous jump in both magnetization and electrical resistivity, sharply contrasting the current-free state. We argue that nonequilibrium electron occupancies of the t2g orbitals stabilized by applied current drive the observed lattice changes and thereby the novel phenomena in this system. Finally, we note that current-induced diamagnetism reported in recent literature [C. Sow et al., Science 358, 1084 (2017).] is not discerned in either slightly doped or pure Ca2RuO4.
