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

TL;DR

This paper introduces atomic layer-by-layer laser molecular beam epitaxy (ALL-Laser MBE), a novel technique that enables precise construction of oxide interfaces and heterostructures with atomic control, leading to new material properties and high-quality interfaces.

Contribution

The paper demonstrates the development and application of ALL-Laser MBE, combining reactive molecular-beam epitaxy and pulsed-laser deposition for advanced oxide material fabrication.

Findings

Produced high-quality conducting LaAlO3/SrTiO3 interfaces at high oxygen pressures.

Achieved interfaces with no oxygen vacancies, unlike previous methods.

Carrier density matches electronic reconstruction predictions.

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 here, with examples of Sr1+xTi1-xO3+delta, Ruddlesden-Popper phase Lan+1NinO3n+1 (n = 4), and LaAl1+yO3(1+0.5y)/SrTiO3 interfaces, 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 and control over stoichiometry. With ALL-Laser MBE 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.