Electronic Excited States at the NaCl/Ag(100) Interface

ORAL

Abstract

The alkali halide/metal interface represents a model insulator/metal system and has attracted much attention recently for their ability to decouple molecular properties from bulk metal. There are, however, few time resolved studies of these systems. We used two photon photoemission to study the dynamics of the electronic states at the NaCl/Ag(100) interface. We find a series of image potential states, where the lowest lying (n=1) member of the series is hybridized with the conduction band of NaCl. Electrons in this hybrid state undergo significant trapping, as shown by a change in their energy and spatial extent on the ultrafast time scale. Our studies correlate coverage and temperature with the dynamics and energetic trapping of electrons in this state. Momentum resolved measurements reveal that electrons in this state are initially delocalized, but become localized within a few hundred femtoseconds either due to small polaron formation or trapping at a defect. Qualitatively similar behavior has been observed for several other alkali halides on both the Ag(100) and Ag(111) surfaces, proving the generality of the phenomenon.

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Authors

  • David Suich

    University of California - Berkeley

  • Sergey Savrasov

    Hartnell College, Cal State Univ- Long Beach, University of California, Davis, School of Natural Science, University of California, Merced, Seagate Technology, Materials Science and Engineering, National Tsing Hua University, Taiwan, University of California - Berkeley, University of Colorado, Boulder -- Dept of Physics, University of California, Berkeley -- Dept of Chemistry, UC Merced, California State University, Fresno, California Institute of Technology, California State University, Long Beach, La Canada Flintridge, CA, Department of Physics, Florida A\&M University, Tallahassee, FL-32307, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA-94550, Cal State Univ East Bay, American River College, UC Santa Cruz, Notre Dame High School, Benedict College, Lawrence Livermore National Laboratory, Tuskegee University, California State University, Dominguez Hills, Sonoma State University, Carnegie Observatories, University of California, Los Angeles, Institute of Astronomy, University of Cambridge, UK, University of California, Santa Barbara, University of Alabama, MPIfR, Bonn, Germany, Stanford University, University of California - Davis

  • Sergey Savrasov

    Hartnell College, Cal State Univ- Long Beach, University of California, Davis, School of Natural Science, University of California, Merced, Seagate Technology, Materials Science and Engineering, National Tsing Hua University, Taiwan, University of California - Berkeley, University of Colorado, Boulder -- Dept of Physics, University of California, Berkeley -- Dept of Chemistry, UC Merced, California State University, Fresno, California Institute of Technology, California State University, Long Beach, La Canada Flintridge, CA, Department of Physics, Florida A\&M University, Tallahassee, FL-32307, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA-94550, Cal State Univ East Bay, American River College, UC Santa Cruz, Notre Dame High School, Benedict College, Lawrence Livermore National Laboratory, Tuskegee University, California State University, Dominguez Hills, Sonoma State University, Carnegie Observatories, University of California, Los Angeles, Institute of Astronomy, University of Cambridge, UK, University of California, Santa Barbara, University of Alabama, MPIfR, Bonn, Germany, Stanford University, University of California - Davis

  • Sergey Savrasov

    Hartnell College, Cal State Univ- Long Beach, University of California, Davis, School of Natural Science, University of California, Merced, Seagate Technology, Materials Science and Engineering, National Tsing Hua University, Taiwan, University of California - Berkeley, University of Colorado, Boulder -- Dept of Physics, University of California, Berkeley -- Dept of Chemistry, UC Merced, California State University, Fresno, California Institute of Technology, California State University, Long Beach, La Canada Flintridge, CA, Department of Physics, Florida A\&M University, Tallahassee, FL-32307, Physical and Life Sciences, Lawrence Livermore National Laboratory, Livermore, CA-94550, Cal State Univ East Bay, American River College, UC Santa Cruz, Notre Dame High School, Benedict College, Lawrence Livermore National Laboratory, Tuskegee University, California State University, Dominguez Hills, Sonoma State University, Carnegie Observatories, University of California, Los Angeles, Institute of Astronomy, University of Cambridge, UK, University of California, Santa Barbara, University of Alabama, MPIfR, Bonn, Germany, Stanford University, University of California - Davis