Resumo

MILLAN, B.; HERNANDEZ-HERNANDEZ, I. J.; PEREZ, L. A.  e  MILLAN, J. Samuel. A comparison of optimal doping behaviors between d− and s*− wave superconducting ground states. Rev. mex. fis. [online]. 2021, vol.67, n.2, pp.312-317.  Epub 16-Fev-2022. ISSN 0035-001X.  https://doi.org/10.31349/revmexfis.67.312.

In a previous work reported in this journal, the thermodynamical properties of d-wave superconducting ground states close to half filling were obtained by using a generalized Hubbard model. In the present work, extended s-wave (s*) symmetry superconducting ground states are considered within the same model and a comparison is made between these two symmetries for those properties depending on the carrier density (n) and first- (t) and second-neighbor (t’) electron hopping parameters. For s*-wave superconducting states, the electron-electron interaction Hamiltonian parameters is fixed as in the d-wave case with ∆t = 0.5 eV, ∆t3 = 0.05 eV, and two cases were studied; U = 0 and U = 2 eV. Without considering the diluted regime (n → 0), in the interval n ∈ [0,1], for both symmetries, the maximum critical temperatures (Tc,max) at optimal doping (nop) are lower than those attained at high electron densities n ∈ [1,2]. The superconducting gap at T = 0 K and the corresponding ground state energy (Eg), for all the carrier concentrations, were also obtained. The superconductor state with d-wave symmetry does not depend on U and a supremum for nop(nop,sup), where both Tc,max (nop,t’ and Eg(nop,t’ are minimum, can be found close to half filling. However, in general, for a s*-wave superconductor Tc,max and Eg attain their minimum values at different (nop,t’) points and a nop,sup cannot be properly defined.

Palavras-chave : Theories and models of superconducting state; pairing symmetries (other than s-wave); pseudogap regime.