From manipulating oxide surface to thin film fabrications by Molecular Beam Epitaxy

Condensed Matter Seminars

Speaker: Fengmiao Li, UBC
Date & Time: Friday, 2017-08-04 13:00 - 14:00
Location: AMPEL #311
Local Contact: George Sawatzky
Intended Audience:

Molecular Beam Epitaxy (MBE) is a very powerful technique with the capabilities to manipulate material properties with atomic precision and grow very high-quality metastable thin films and heterostructures in which new electronic states have large probabilities to emerge especially for the compounds with strong electron correlations such as the transition-metal and rare-earth oxides. For example, at the LaAlO3/SrTiO3 interface numerous novel states have been discovered such as the high-mobility two-dimensional electron gas, superconductivity and magnetism stemming from the charge transfer from the polar LaAlO₃ film to SrTiO3 surface. In this talk, I’ll firstly show detail studies of the widely-used SrTiO3 substrate polar (110) surface, focusing on the manipulations of its surface atomic structure and electronic state by the sub-monolayer metal deposition on surface with MBE technique. Then shift to the metastable oxide thin films, the high-temperature superconductor parent compound strontium bismuthate (SrBiO3), and the superconductor titanium monoxide (TiO) with low cation oxide state, which are successfully fabricated by MBE in recent. Some growth details will be talked and their electronic structures will be discussed based on the data of electron and x-ray spectroscopies and density functional calculations. At last, I will present our very recent theoretical studies of the photoelectron energy loss process in photoemission spectroscopy which can very well explain replica bands recently observed by angle-resolved photoemission spectroscopy (ARPES) on the single-layer FeSe/SrTiO3(001) and other ionic material surfaces.