Exploring quasiparticles in high-<i>T</i>_ccuprates through photoemission, tunneling, and x-ray scattering experiments

Abstract

One of the key challenges in the field of high-temperature superconductivity\nis understanding the nature of fermionic quasiparticles. Experiments\nconsistently demonstrate the existence of a second energy scale, distinct from\nthe d-wave superconducting gap, that persists above the transition temperature\ninto the "pseudogap" phase. One common class of models relates this energy\nscale to the quasiparticle gap due to a competing order, such as the\nincommensurate "checkerboard" order observed in scanning tunneling microscopy\n(STM) and resonant elastic X-ray scattering (REXS). In this paper we show that\nthese experiments are better described by identifying the second energy scale\nwith the inverse lifetime of quasiparticles. We develop a minimal\nphenomenological model that allows us to quantitatively describe STM and REXS\nexperiments and discuss their relation with photoemission spectroscopy. Our\nstudy refocuses questions about the nature of the pseudogap phase to the study\nof the origin of inelastic scattering.\n