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First- and Second Order Phase Transitions in the Holstein-Hubbard Mode
First- and Second Order Phase Transitions in the Holstein-Hubbard Mode
Koller, W.
Meyer, D.
Ono, Y.
Hewson, A. C.
We investigate metal-insulator transitions in the half-filled Holstein-Hubbard model as a function of the on-site electron-electron interaction U and the electron-phonon coupling g. We use several different numerical methods to calculate the phase diagram, the results of which are in excellent agreement. When the electron-electron interaction U is dominant the transition is to a Mott-insulator; when the electron-phonon interaction dominates, the transition is to a localised bipolaronic state. In the former case, the transition is always found to be second order. This is in contrast to the transition to the bipolaronic state, which is clearly first order for larger values of U. We also present results for the quasiparticle weight and the double-occupancy as function of U and g.
IOP Publishing
2004-05
jpn
journal article
http://hdl.handle.net/10191/26872
https://niigata-u.repo.nii.ac.jp/records/1647
info:doi/10.1209/epl/i2003-10228-6
AA10668127
02955075
Europhysics Letters
Europhysics Letters
66
4
559
564
https://niigata-u.repo.nii.ac.jp/record/1647/files/1014.pdf
application/pdf
102.5 kB
2019-07-29