Effects of electron-phonon coupling on the metal-insulator transition inLa2−xSrxCuO4superconductors

2003 ◽  
Vol 67 (15) ◽  
Author(s):  
Changjin Zhang ◽  
Yuheng Zhang
Keyword(s):  
Insulator Transition ◽  
Phonon Coupling ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Electron Phonon Coupling

Polaron Crystallization and the Metal–Insulator Transition

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3131-3136 ◽  
Author(s):  
P. Quémerais ◽  
S. Fratini
Keyword(s):  
Physical Mechanism ◽  
Insulator Transition ◽  
Vibrational Modes ◽  
Zero Temperature ◽  
Phonon Coupling ◽  
Metal Insulator Transition ◽  
Strong Electron ◽  
Metal Insulator ◽  
Electron Phonon Coupling ◽  
Polar Materials

The Crystallization of polarons at finite density, due to the long-range Coulomb forces — when no bipolarons can be formed — is discussed close to the metal–insulator transition (MIT). As a function of the density, the melting is examined at zero temperature. By calculating the quantum fluctuations of both the electron and the polarization, we show that at strong electron–phonon coupling the dissociation of the polarons at the MIT is favored, rather than the melting towards a polaron liquid. In this regime, we demonstrate, that an instability of the transverse vibrational modes of the polaron crystal occurs as the density increases. This provides a new physical mechanism for the MIT in polar materials, for which an experimental signature is predicted.

scholarly journals ELECTRON-PHONON COUPLING CLOSE TO A METAL-INSULATOR TRANSITION IN ONE DIMENSION

1996 ◽  
Vol 10 (12) ◽  
pp. 1439-1451 ◽  
Author(s):  
MICHELE FABRIZIO ◽  
CLAUDIO CASTELLANI ◽  
CARLO DI CASTRO
Keyword(s):  
Electronic System ◽  
Insulator Transition ◽  
Dimensional System ◽  
Phonon Coupling ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
One Dimensional ◽  
Electron Phonon Coupling ◽  
Short Range Repulsion ◽  
Half Filling

We consider a one-dimensional system of electrons interacting via a short-range repulsion and coupled to phonons close to the metal-insulator transition at half-filling. We argue that the metal-insulator transition can be described as a standard one-dimensional incommensurate to commensurate transition, even if the electronic system is coupled to the lattice distortion. By making use of known results for this transition, we prove that low-momentum phonons, with the inclusion of the 4kF (≃2π near half-filling) scattering, do not play any relevant role close to the metal-insulator transition, unless their coupling to the electrons is large in comparison with the other energy scales present in the problem. In other words the effective strength of the low-momentum transferred electron-phonon coupling does not increase close to the metal-insulator transition, even though the effective velocity of the mobile carriers is strongly diminished.

scholarly journals Volume-Based Considerations for the Metal-Insulator Transition of CMR Oxides

1997 ◽  
Vol 494 ◽  
Author(s):  
J. J. Neumeier ◽  
A. L. Cornelius ◽  
M. F. Hundley ◽  
K. Andres ◽  
K. J. McClellan
Keyword(s):  
Electrical Resistivity ◽  
Thermal Expansion ◽  
Phase Transitions ◽  
Applied Pressure ◽  
Phonon Coupling ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Resistivity Data ◽  
Volume Dependence ◽  
Electron Phonon Coupling

ABSTRACTThe sensitivity of ρ to changes in volume which occur through: (1) applied pressure, (2) variations in temperature, and (3) phase transitions, is evaluated for some selected CMR oxides. It is argued that the changes in volume associated with (2) and (3), which are referred to as self pressures, are equivalent in magnitude to changes in volume resulting from pressures in the range of 0.18 to 0.45 GPa. Through consideration of thermal expansion and electrical resistivity data, it is shown that these self pressures are responsible for large features in the electrical resistivity and are an important component for the occurrence of the metallicity below Tc. It is suggested that this is a manifestation of a strong volume dependence of the electron phonon coupling in the CMR oxides.

Fermi-surface reconstruction close to a pressure-induced metal-insulator transition

2004 ◽  
Vol 114 ◽  
pp. 277-281 ◽  
Author(s):  
J. Wosnitza ◽  
J. Hagel ◽  
O. Stockert ◽  
C. Pfleiderer ◽  
J. A. Schlueter ◽  
...  
Keyword(s):  
Fermi Surface ◽  
Surface Reconstruction ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Fermi Surface Reconstruction
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