High-resolution angle-resolved photoemission measurements have been carried out on Sr 2RuO 4. We observe clearly two sets of Fermi surface sheets near the (π,0)-(0,π) line, which are most likely attributed to the surface and bulk Fermi surface splitting of the β band. This is in strong contrast to the nearly null surface and bulk Fermi surface splitting of the α band, although both have identical orbital components. Extensive band structure calculations are performed by considering various scenarios, including structural distortion, spin-orbit coupling, and surface ferromagnetism. However, none of them can explain such a qualitative difference of the surface and bulk Fermi surface splitting between the α and β sheets. This unusual behavior points to an unknown order on the surface of Sr 2RuO 4 that remains to be uncovered. Its revelation will be important for studying and utilizing novel quantum phenomena associated with the surface of Sr 2RuO 4 as a result of its being a possible p-wave chiral superconductor and a topological superconductor.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Oct 10 2012|
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics