Atomic and electronic structure of ultra-thin Al/AlOx/Al interfaces

Interfaces between metals based on AlO$_{x}$ represent the most popular basis for Josephson junctions or, more recently, also for junctions exhibiting substantial tunneling magneto-resistance. We have performed a computational study of possible local geometric structures of such interfaces at the ab-initio DFT/GGA level of approximation to complement recent experimental data on ultra-thin AlO$_{x}$-based interfaces. We present two competing structures that we characterise with their electronic properties: fragmentation and interface energies.