In the past few decades, researchers have focused much attention on complex oxides—oxide compounds in which the electrons interact strongly with one another and with the lattice. Such compounds exhibit a fascinating range of properties: ferromagnetism, ferroelectricity, high-temperature superconductivity, colossal magnetoresistance, and spin-glass behaviors. Not surprisingly, these compounds are being explored for myriad applications.
Interfaces between complex-oxide materials may yield even richer behavior than is found in bulk. Perhaps the interfaces exhibit phases that don’t exist in either of the constituent compounds. Just look at the wide variety of electronic devices that arise from the merging of semiconductors: One striking example is the quantum Hall effect seen in the 2D electron gas formed at a gallium arsenide–aluminum gallium arsenide heterojunction.
Like semiconductors, many complex oxides are closely lattice-matched to one another and lend themselves to epitaxial growth. Only in the past decade, however, have experimenters honed the techniques to grow...
