Novel Two-Dimensional Electron Liquid States in Quantum Well Structures of Strongly Correlated Oxides

The quantum confinement of strongly correlated electrons in artificial structures has heralded the possibility of creating the novel quantum materials with extraordinary physical properties. By optimally combining sophisticated oxide growth techniques and advanced analysis techniques using synchrotron radiation, we have designed and controlled the novel quantum phenomena emerging in oxide artificial structures. The observed metallic quantum-well states in digitally controlled ultrathin films of strongly correlated oxide SrVO3 exhibit characteristic features reflecting their strongly correlated nature. Furthermore, the structural controllability of the quantum-well structures enables us to investigate how the electronic structure changes as a function of dimensionality. The present study demonstrates that the quantum-well structure of strongly correlated oxides will provide a new strategy for both investigating the behavior of correlated electrons under varying interactions among their spin, charge, and orbital degrees of freedom and for manipulating novel quantum phenomena in reduced dimensions.