The quasi two-dimension electron system (q2DES) that forms at the interface between LaAlO3 (LAO) and SrTiO3 (STO) has attracted much attention from the oxide electronics community. Indeed, it has emerged as a platform to test a cornucopia of low-dimensional physical effects, such as two-dimensional superconductivity, quantum Hall effect, spin-charge conversion through the inverse Rashba-Edelstein effect or electron pairing without superconductivity, to name just a few. The LAO/STO q2DES possesses several hallmark features; one is the existence of a critical LAO thickness of 4 unit-cells (uc) for interfacial conductivity to emerge. Another is the extreme sensitivity of its transport properties to electrostatic boundary conditions. This surface-interface coupling was previously exploited to modulate both carrier densities and mobilities of the q2DES through the controlled adsorption of polar solvents[7–11] and by capping with different materials[12,13]. More spectacularly, first-principles calculations have suggested that the critical thickness could be reduced to just 1 uc by covering the LAO film with specific metals, an effect we recently demonstrated experimentally for Co. However, the underlying mechanism leading to the formation of the q2DES in these Co/LAO(1 uc)/STO samples remains unclear.
|Publication status||Published - 2017 Aug 30|
- Two-dimensional electron gas
- X-ray photoemission
ASJC Scopus subject areas