Evidence of dynamic Jahn-Teller distortions in two-dimensional crystalline molecular films

Authors

• Jaewu Choi, University of Nebraska-LincolnFollow
• Peter A. Dowben, University of Nebraska-LincolnFollow
• C.N. Borca, University of Nebraska-Lincoln
• Shireen Adenwalla, University of Nebraska-LincolnFollow
• A.V. Bune, University of Nebraska-Lincoln
• Stephen Ducharme, University of NebraskaFollow
• V.M. Fridkin, Institute of Crystallography, The Russian Academy of Sciences, 117333 Moscow, Russia
• S.P. Palto, Institute of Crystallography, The Russian Academy of Sciences, 117333 Moscow, Russia
• N. Petukhova, Institute of Crystallography, The Russian Academy of Sciences, 117333 Moscow, Russia

Document Type

Article

Date of this Version

1-15-1999

Comments

Published by American Physical Society. Copyright 1999. Permission to use. Phys. Rev. B 59 (1999) 1819-1824. http://prb.aps.org/

Abstract

The surface electronic structure in crystalline copolymer films of vinylidene fluoride (70%) with trifluoroethylene (30%) has been studied by photoemission and inverse photoemission as a function of alkali metal (sodium) doping. Sodium doping introduces at least two new states into the band (HOMO-LUMO) gap well away from the Fermi level. While the sodium-doped copolymer is observed to resemble an n-type semiconductor, the change in electronic structure with temperature suggests that dynamic distortions lead to a photoemission initial state splitting of the lower Hubbard-like bands. There is a decrease in the effective Debye temperature with sodium doping which may, in turn, enhance the dynamic Jahn-Teller distortion.