Direct observation of surface-induced orbital order with scanning tunneling microscopy. Novel ordering phenomena on a surface

Orbital-mediated quantum phenomena have proved over the past decade to be far-reaching and complex as exemplified in orbital orders, orbital-fluctuation-mediated superconductivity, orbital Kondo effect, and multipole-moment ordering. Recent progress of a scanning tunneling microscope (STM) has enabled orbital-selective tunneling by fine-tuning the tip-sample distance. We exploit this orbital sensitivity of STM to unveil a surface-induced cobalt d-orbital order in the heavy fermion compound CeCoIn₅, together with first principles calculations. (author)