Doping-dependent band structure of LaAlO$_{3}$/SrTiO$_{3}$ interfaces by soft x-ray polarization-controlled resonant angle-resolved photoemission

摘要

Polarization-controlled synchrotron radiation was used to map the electronicstructure of buried conducting interfaces of LaAlO$_3$/SrTiO$_3$ in a resonantangle-resolved photoemission experiment. A strong dependence on the lightpolarization of the Fermi surface and band dispersions is demonstrated,highlighting the distinct Ti 3d orbitals involved in 2D conduction. Sampleswith different 2D doping levels were prepared and measured by photoemission,revealing different band occupancies and Fermi surface shapes. A directcomparison between the photoemission measurements and advanced first-principlecalculations carried out for different 3d-band fillings is presented inconjunction with the 2D carrier concentration obtained from transportmeasurements.