Epitaxy-distorted spin-orbit Mott insulator in Sr2IrO4 thin films

作者：Serrao C Rayan^*; Liu Jian; Heron J T; Singh Bhalla G; Yadav A; Suresha S J; Paull R J; Yi D; Chu J H; Trassin M; Vishwanath A; Arenholz E; Frontera C; Zelezny J; Jungwirth T; Marti X; Ramesh R

来源：Physical Review B, 2013, 87(8): 085121.

DOI：10.1103/PhysRevB.87.085121

High-quality epitaxial thin films of J(eff) = 1/2 Mott insulator Sr2IrO4 with increasing in-plane tensile strain have been grown on top of SrTiO3(001) substrates. Increasing the in-plane tensile strain up to similar to 0.3% was observed to drop the c/a tetragonality by 1.2%. X-ray absorption spectroscopy detected a strong reduction of the linear dichroism upon increasing in-plane tensile strain towards a reduced anisotropy in the local electronic structure. While the most relaxed thin film shows a consistent dependence with previously reported single crystal bulk measurements, electrical transport reveals a charge gap reduction from 200 meV down to 50 meV for the thinnest and most epitaxy-distorted film. We argue that the reduced tetragonality plays a major role in the change of the electronic structure, which is reflected in the change of the transport properties. Our work opens the possibility for exploiting epitaxial strain as a tool for both structural and functional manipulation of spin-orbit Mott systems. DOI: 10.1103/PhysRevB.87.085121

• 出版日期2013-2-15