title: Particle-Hole Asymmetry in the Cuprate Pseudogap Measured with Time-Resolved Spectroscopy.
abstract: One of the most puzzling features of high-temperature cuprate superconductors is the pseudogap state, which appears above the temperature at which superconductivity is destroyed. There remain fundamental questions regarding its nature and its relation to superconductivity. But to address these questions, we must first determine whether the pseudogap and superconducting states share a common property: particle-hole symmetry. We introduce a new technique to test particle-hole symmetry by using laser pulses to manipulate and measure the chemical potential on picosecond time scales. The results strongly suggest that the asymmetry in the density of states is inverted in the pseudogap state, implying a particle-hole asymmetric gap. Independent of interpretation, these results can test theoretical predictions of the density of states in cuprates.
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Tristan L
authors.initials: TL
authors.lastname: Miller
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Wentao
authors.initials: W
authors.lastname: Zhang
authors.affiliation: Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki 305-8568, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Eisaki
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Physics, University of California, Berkeley, California 94720, USA.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Lanzara