Structural distortions at polar manganite interfaces

Electronic, lattice, and spin interactions at the interfaces between crystalline complex transition-metal oxides can give rise to a wide range of functional electronic and magnetic phenomena not found in bulk. At heterointerfaces, these interactions may be enhanced by combining oxides where the polarity changes at the interface. The physical structure between nonpolar SrTiO3 and polar La1-xSrxMnO3 (x=0.2) is investigated using high-resolution synchrotron x-ray diffraction to directly determine the role of structural distortions in compensating the polar discontinuity. At both the oxide-oxide interface and vacuum-oxide interfaces, the lattice is found to expand and rumple along the growth direction. The SrTiO3/La1-xSrxMnO3 interface also exhibits intermixing of La and Sr over a few unit cells. The results thus demonstrate that polar distortions and ionic intermixing coexist and both pathways play a significant role at interfaces with polar discontinuities.

Duke Scholars

Author Divine P Kumah Physics