title: Optical probing of ultrafast electronic decay in Bi and Sb with slow phonons.
abstract: Illumination with laser sources leads to the creation of excited electronic states of particular symmetries, which can drive isosymmetric vibrations. Here, we use a combination of ultrafast stimulated and cw spontaneous Raman scattering to determine the lifetime of A(1g) and E(g) electronic coherences in Bi and Sb. Our results both shed new light on the mechanisms of coherent phonon generation and represent a novel way to probe extremely fast electron decoherence rates. The E(g) state, resulting from an unequal distribution of carriers in three equivalent band regions, is extremely short lived. Consistent with theory, the lifetime of its associated driving force reaches values as small as 2 (6) fs for Bi (Sb) at 300 K.
authors.affiliation: Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Li
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Chen
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA and Departments of Photon Science and Applied Physics, Stanford University, Stanford, CA 94309, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Reis
authors.affiliation: Tyndall National Institute and Department of Physics, University College, Cork, Ireland.
authors.forename: S
authors.initials: S
authors.lastname: Fahy
authors.affiliation: Department of Physics, University of Michigan, Ann Arbor, MI 48109-1040, USA.
authors.forename: R
authors.initials: R
authors.lastname: Merlin