Electronic structure of the cuprate superconducting and pseudogap phases from spectroscopic imaging STM

We survey the use of spectroscopic imaging scanning tunneling microscopy (SI-STM) to probe the electronic structure of underdoped cuprates. Two distinct classes of electronic states are observed in both the d-wave superconducting (dSC) and the pseudogap (PG) phases. The first class consists of the dispersive Bogoliubov quasiparticle excitations of a homogeneous d-wave superconductor, existing below a lower energy scale E =10. We find that the Bogoliubov quasiparticle interference (QPI) signatures of delocalized Cooper pairing are restricted to a k-space arc, which terminates near the lines connecting k=±(π/a0, 0) to k=±(0, π/a0). This arc shrinks continuously with decreasing hole density such that Luttinger’s theorem could be satisfied if it represents the front side of a hole-pocket that is bounded behind by the 8 Author to whom any correspondence should be addressed. New Journal of Physics 13 (2011) 00000