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

摘要

Advancements in nanoscale engineering of oxide interfaces andheterostructures have led to discoveries of emergent phenomena and newartificial materials. Combining the strengths of reactive molecular-beamepitaxy and pulsed-laser deposition, we show here, with examples ofSr1+xTi1-xO3+delta, Ruddlesden-Popper phase Lan+1NinO3n+1 (n = 4), andLaAl1+yO3(1+0.5y)/SrTiO3 interfaces, that atomic layer-by-layer lasermolecular-beam epitaxy (ALL-Laser MBE) significantly advances the state of theart in constructing oxide materials with atomic layer precision and controlover stoichiometry. With ALL-Laser MBE we have produced conductingLaAlO3/SrTiO3 interfaces at high oxygen pressures that show no evidence ofoxygen vacancies, a capability not accessible by existing techniques. Thecarrier density of the interfacial two-dimensional electron gas thus obtainedagrees quantitatively with the electronic reconstruction mechanism.