Photoelectron spectroscopic study of the temperature-dependent termination of the LaAlO3(100) surface

The temperature-dependent termination of the LaAlO3(100) surface has been studied by variable temperature angle-resolved monochromatic X-ray photoelectron spectroscopy. A high binding energy component in the Al 2p spectrum observed at T<150°C is absent at T>250°C; its presence and absence as a function of temperature are reversible. This component, also found to be localized to the outermost surface layer, exhibits trends consistent with the temperature-dependent rearrangement known to occur on the LaAlO3(100) surface, i.e. Al–O or La–O terminations below 150°C and above 250°C, respectively. The driving force behind this rearrangement is believed to be an oxygen deficiency in the 1st-atomic layer.