Coherent quasiparticles with a small fermi surface in lightly doped Sr(3)Ir(2)O(7)

his work was funded by the Swiss National Science Foundation (Grant No. 200021-146995), the UK Royal Society, the UK-EPSRC, and the European Research Council (Grant No. ERC-319286 QMAC). We characterize the electron doping evolution of (Sr1-xLax)3Ir2O7 by means of angle-resolved photoemission. Concomitant with the metal insulator transition around x ≈ 0.05 we find the emergence of coherent quasiparticle states forming a closed small Fermi surface of volume 3x/2, where x is the independently measured La concentration. The quasiparticle weight Z remains large along the entire Fermi surface, consistent with the moderate renormalization of the low-energy dispersion, and no pseudogap is observed. This indicates a conventional, weakly correlated Fermi liquid state with a momentum independent residue Z ≈ 0.5 in lightly doped Sr3Ir2O7. Publisher PDF