What EELS Spectra Tell Us About Manganite/ferroelectric Interfaces: Ab Initio Results

The interplay of structure, electronic states, and magnetism is a rich field of research for transition metal oxides. Manganese oxides are well known for the dependence of their magnetic state and resistivity on doping (colossal magnetoresistance) which can be modified by chemical alloying or dynamically via the ferroelectric field effect. We focus on the interface between an oxide ferroelectric and the manganite La$_x$Sr$_{1-x}$MnO$_3$ where it has already been established that there is a dramatic coupling of atomic geometry, electronic structure and magnetism which leads to a very large magnetoelectric coupling. In this work, we use first principles theory to understand what observed atomically-resolved EELS spectra on such systems tell us about the interfacial structure and electronic properties. By understanding the link between EELS and atomic-scale structure at an oxide interface, one can then more confidently interpret experimental results to understand interfaces of novel materials, particularly correlated electron systems.