SPIN AND CHARGE PSEUDOGAPS FOLLOWING KONDO EFFECT IN THE NORMAL STATE OF THE UNDERDOPED CUPRATES

Abstract

A study of experimental results on various parameters of underdoped cuprates in the normal state combined with analytic calculation of Hall parameters assuming a two-channel Kondo model for the system leads to the conclusion that the spin and charge pseudogaps are, respectively, a Kondo hybridisation gap and an incipient d-wave "superconducting" gap. The former occurs due to resonant scattering of doped holes by the magnetic Cu 2+ ions while the latter occurs due to incoherent Cooper pairing of Kondo-compensated quasi-itinerant Cu d-orbitals via exchange of spin excitations. We comment on the essential similarity of the high-T c and heavy fermion superconductors and a certain crossover at lower temperatures from the two-channel to the one-channel Kondo model. An expression has been derived for the Kondo contribution to the spectral function of the charge pseudogap. We believe this work unravels the long-standing conundrum of the high-T c cuprates.