Anomalous Hall effect at the spontaneously electron-doped polar surface of PdCoO_{2} ultrathin films

We revealed the electrical transport through surface ferromagnetic states of a nonmagnetic metal PdCoO_{2}. Electronic reconstruction at the Pd-terminated surface of PdCoO_{2} induces Stoner-like ferromagnetic states, which could lead to spin-related phenomena among the highly conducting electrons in PdCoO_{2}. Fabricating a series of nanometer-thick PdCoO_{2} thin films, we detected a surface-magnetization-driven anomalous Hall effect via systematic thickness- and termination-dependent measurements. Besides, we discuss that finite magnetic moments in electron doped CoO_{2} triangular lattices may have given rise to additional unconventional Hall resistance.