Constructing oxide interfaces and heterostructures by atomic layer-by-layer laser molecular beam epitaxy

Advancementsn nanoscale engineering of oxide interfaces and he o ructures have led to discoveries of er en phenomena and new artificial materials. Combining the strengths of reactive molecular-beam epitaxy and pulsed-laserdeposition, we show here,with examples of Sr1+xTi1-xO3+delta, Ruddlesden-Popper phase La NinO3n+1 (n=4), and LaAl1+yO3((1+O5y))/SrTiO3 interfaces,,that atomic layer-by-layer laser molecular-beam epitaxy significantly advances the state of the art in constructing oxide materials with atomic layer precision and control over stoichiometry. With atomic layer-by-layer laser molecular-beam epitaxy we have produced' conducting LaAlO3/SrTiO3 interfaces at high oxygen pressures that show no evidence of oxygen vacancies, a capability not accessible by existing techniques. The carrier density of the interfacial two-dimensional electron gas thus obtained agrees quantitatively with the electronic reconstruction mechanism.