Doping Evolution of Nodal Electron Dynamics in Trilayer Cuprate Superconductor Bi${}_2$Sr${}_2$Ca${}_2$Cu${}_3$O${}_{10+\hat{I}´}$ Revealed by Laser-Based Angle-Resolved Photoemission Spectroscopy

Abstract

The doping evolution of the nodal electron dynamics in the trilayer cuprate superconductor Bi${}_2$Sr${}_2$Ca${}_2$Cu${}_3$O${}_{10+\hat{I}´}$ (Bi2223) is investigated using high-resolution laser-based angle-resolved photoemission spectroscopy (ARPES). Bi2223 single crystals with different doping levels are prepared by controlled annealing which cover the underdoped, optimally-doped and overdoped regions. The electronic phase diagram of Bi2223 is established which describes the T${}_{\mathrm{c}}$ dependence on the sample doping level. The doping dependence of the nodal Fermi momentum for the outer (OP) and inner (IP) CuO${}_2$ planes is determined. Charge distribution imbalance between the OP and IP CuO${}_2$ planes is quantified, showing enhanced disparity with increasing doping. Nodal band dispersions demonstrate a prominent kink at $\sim$94meV in the IP band, attributed to the unique Cu coordination in the IP plane, while a weaker $\sim$60meV kink is observed in the OP band. The nodal Fermi velocity of both OP and IP bands is nearly constant at $\sim$1.62eVÃ independent of doping. These results provide important information to understand the origin of high T${}_{\mathrm{c}}$ and superconductivity mechanism in high temperature cuprate superconductors.

18 pages, 4 figures