Peierls instability and superconductivity in quasionedimensional conductors
Abstract
The transition temperature of the Peierls phase (T_{P}) and of the superconducting phase (T_{s}) are studied, including a hoppingtype interchain coupling and retardation effects due to finite bare phonon frequency ω_{0}. The interactions between the electrons include large and small momentum transfers with attractive couplings s_{1}, s_{2}, respectively. The set of most diverging diagrams is summed and the coexistence line (for which T_{P}=T_{s}) is shown to be s_{1}=2s_{2} for the nonretarded interaction. For s_{1}≠2s_{2} the two phases exclude each other. For a finite (ω)_{0}, increasing (ω)_{0} is shown to increase T_{s} while decrease T_{P}. Higher temperatures T_{s} are possible if (a) ω_{0} is higher; (b) s_{1}, s_{2} are stronger, but s_{1} must stay below a critical value determined by s_{2} and ω_{0} (for s_{2}=1, (T_{s})~=ω_{0}20) (c) the commensurate case is avoided; (d) the Peierls instability is suppressed, i.e., by a large enough interchain coupling. The dependence of T_{P} on ω_{0} implies a positive isotope shift which is measurable if ω_{0}>~2πT_{P}. Such highfrequency phonons are important for hightemperature superconductivity and the isotope shift provides a method for locating them in the Peierls phase.
 Publication:

Physical Review B
 Pub Date:
 November 1977
 DOI:
 10.1103/PhysRevB.16.3943
 Bibcode:
 1977PhRvB..16.3943H