Heavy d-electron quasiparticle interference and real-space electronic structure of Sr ₃ Ru ₂ O ₇

The intriguing idea that strongly interacting electrons can generate spatially inhomogeneous electronic liquid-crystalline phases is over a decade old ^1-5 , but these systems still represent an unexplored frontier of condensed-matter physics. One reason is that visualization of the many-body quantum states generated by the strong interactions, and of the resulting electronic phases, has not been achieved. Soft condensed-matter physics was transformed by microscopies that enabled imaging of real-space structures and patterns. A candidate technique for obtaining equivalent data in the purely electronic systems is spectroscopic imaging scanning tunnelling microscopy (SI-STM). The core challenge is to detect the tenuous but heavy momentum (k)-space components of the many-body electronic state simultaneously with its real-space constituents. ₃ Ru ₂ O ₇ provides a particularly exciting opportunity to address these issues. It possesses a very strongly renormalized heavy d-electron Fermi liquid ^6,7 and exhibits a field-induced transition to an electronic liquid- crystalline phase ^8,9 . Finally, as a layered compound, it can be cleaved to present an excellent surface for SI-STM.