AVS 47th International Symposium
    Surface Science Monday Sessions
       Session SS2+EL-MoA

Invited Paper SS2+EL-MoA1
Recent Photoemission Studies of Quasi-1D Solids

Monday, October 2, 2000, 2:00 pm, Room 209

Session: Electronic Structure and Excitations
Presenter: K.E. Smith, Boston University
Authors: K.E. Smith, Boston University
J. Xue, Boston University
L.C. Duda, Boston University
A. Fedorov, Brookhaven National Laboratory
P.D. Johnson, Brookhaven National Laboratory
W. McCarroll, Rutgers University
M. Greenblatt, Rutgers University
Correspondent: Click to Email
Much controversy surrounds the interpretation of the results of angle resolved photoemission spectroscopy (ARP) studies of the electronic structure of quasi one-dimensional (1D) solids. In principle, ARP should provide valuable information about quasi-1D solids, including the structure of the Fermi surface and possible non-Fermi liquid behavior of electrons close to the Fermi level (E@sub F@). In practice, straightforward interpretation of the spectra is often difficult. It has been reported that photoemission from states near E@sub F@ in quasi-1D conductors differs significantly from that measured from two and three dimensional solids. There are a number of possible explanations for these observations, including problems with surface defects and stoichiometry, charge density wave fluctuations leading to a pseudogap, or a Luttinger liquid state. We report here the results of a temperature dependent ARP study of the electronic structure close to E@sub F@ in the quasi-1D conductors Li@sub 0.9@Mo@sub 6@O@sub 17@ and K@sub 0.3@MoO@sub 3@.@footnote 1@ These materials are ideal for ARP studies since large high quality crystals can be grown, and surfaces suitable for ARP measurements can be prepared by cleaving in vacuum. Using very high momentum and energy resolution ARP, we clearly measured for both materials: i) quasi-1D bands dispersing across the Fermi surface; ii) substantial emission intensity at E@sub F@ in the metallic phase; and iii) a gap opening at E@sub F@ as the samples are cooled through the metal-semiconductor transition. Our results differ from many earlier ARP studies of quasi-1D solids. The differences are likely due to an order of magnitude improvement in angular resolution (and corresponding improvement in momentum resolution) for the spectrometer used here. The reported non-Fermi liquid behavior in photoemission from these solids will be discussed. @FootnoteText@ Supported in part by the DOE under DE-FG02-98ER45680 (KES) and DE-AC02-98CH10886 (PDJ).