Naslov
Central Peak in the Pseudogap of High T_c Superconductors

Autori
Sunko, Denis K. ; Barišić, Slaven

Izvornik
European physical journal B : condensed matter physics (1434-6028) 46 (2005); 269-279

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
high-temperature superconductors; ARPES; magnetic fluctuations; slave boson

Sažetak
We study the effect of antiferromagnetic (AF) correlations in the three-band Emery model, with respect to the experimental situation in weakly underdoped and optimally doped BSCCO. In the vicinity of the vH singularity of the conduction band there appears a central peak in the middle of a pseudogap, due to an antiadiabatic quasiparticle, which is insensitive to the time scale of the mechanism responsible for the pseudogap. We find a quantum low-temperature regime corresponding to experiment, in which the pseudogap is created by zero-point motion of the magnons, as opposed to the usual semiclassical derivation, where it is due to a divergence of the magnon occupation number. Detailed analysis of the spectral functions along the (pi, 0)-(pi, pi) line show significant agreement with experiment, both qualitative and, in the principal scales, quantitative. The observed slight approaching-then-receding of both the wide and narrow peaks with respect to the Fermi energy is also reproduced. We conclude that optimally doped BSCCO has a well-developed pseudogap of the order of 1000 K. This is only masked by the antiadiabatic quasiparticle, which provides a small energy scale, unrelated to the AF scale, and primarily controlled by the position of the chemical potential.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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