title: Anomalous Metal Phase Emergent on the Verge of an Exciton Mott Transition.
abstract: We investigate the exciton Mott transition (EMT) by using optical pump-terahertz probe spectroscopy on GaAs, with realizing the condition of Mott's gedanken experiment by the resonant excitation of 1s excitons. We show that an anomalous metallic phase emerges on the verge of the EMT as manifested by a peculiar enhancement of the quasiparticle mass and scattering rate. From the temperature and density dependence, the observed anomaly is shown to originate from the electron-hole (e-h) correlation which becomes prominent at low temperatures, possibly suggesting a precursor of e-h Cooper pairing.
authors.affiliation: Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan.|Cryogenic Research Center, The University of Tokyo, Tokyo 113-0032, Japan.
authors.forename: Fumiya
authors.initials: F
authors.lastname: Sekiguchi
authors.affiliation: Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan.
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Mochizuki
authors.affiliation: Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan.
authors.forename: Changsu
authors.initials: C
authors.lastname: Kim
authors.affiliation: Institute of Solid State Physics, The University of Tokyo, Kashiwa 277-8581, Japan.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Akiyama
authors.affiliation: Department of Electrical Engineering, Princeton University, New Jersey 08544, USA.
authors.forename: Loren N
authors.initials: LN
authors.lastname: Pfeiffer
authors.affiliation: Department of Electrical Engineering, Princeton University, New Jersey 08544, USA.
authors.forename: Ken W
authors.initials: KW
authors.lastname: West
authors.affiliation: Department of Physics, The University of Tokyo, Tokyo 113-0033, Japan.|Cryogenic Research Center, The University of Tokyo, Tokyo 113-0032, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Shimano