Past Events

Abstract

Advancements in nanoscale engineering of oxide interfaces and heterostructures have led to discoveries of emergent phenomena and new artificial materials. Combining the strengths of reactive molecular-beam epitaxy and pulsed-laser deposition, we show that atomic layer-by-layer laser molecular-beam epitaxy (ALL-Laser MBE) significantly advances the state of the art in constructing oxide materials with atomic layer precision. Using Sr_1+xTi_1-xO₃ as example, we demonstrate the effectiveness of the technique in producing oxide films with stoichiometric and crystalline perfection. With the growth of La₅Ni₄O₁₃, a Ruddlesden-Popper phase with n = 4 that has never been reported in the literature, we demonstrate that ALL-Laser MBE allows us to push the equilibrium thermodynamic boundary further. By growing LaAl_1+yO₃ films of different stoichiometry on TiO₂-terminated SrTiO₃ substrate at high oxygen pressure, we show that the behavior of the two-dimensional electron gas at the LaAlO₃/SrTiO₃ interface can be quantitatively explained by the electronic reconstruction mechanism. In LaNiO₃ films on LaAlO₃ substrate with LaAlO₃ buffer layer, we observed the metal insulator transition in 1.5 unit cells, which is driven by oxygen vacancies in addition to epitaxial strain and reduced dimensionality.

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