Doping dependence of Meissner effect in cuprate superconductors

Abstract

Within the t-t'-J model, the doping dependence of the Meissner effect in cuprate superconductors is studied based on the kinetic energy driven superconducting mechanism. Following the linear response theory, it is shown that the electromagnetic response consists of two parts, the diamagnetic current and the paramagnetic current, which exactly cancels the diamagnetic term in the normal state, and then the Meissner effect is obtained for all the temperature $T\leq T_{c}$ throughout the superconducting dome. By considering the two-dimensional geometry of cuprate superconductors within the specular reflection model, the main features of the doping and temperature dependence of the local magnetic field profile, the magnetic field penetration depth, and the superfluid density observed on cuprate superconductors are well reproduced. In particular, it is shown that in analogy to the domelike shape of the doping dependent superconducting transition temperature, the maximal superfluid density occurs around the critical doping $\delta\approx 0.195$, and then decreases in both lower doped and higher doped regimes.Comment: 13 pages, 5 figure

Doping Dependence of Meissner Effect in Triangular-Lattice Superconductors

“…In this case, we have fitted the relation between T c and ρ s in the underdoped regime, and the result shows that triangular-lattice superconductors satisfy the similar Uemura relation in the underdoped regime 26,27 . Incorporating the result obtained from square-lattice cuprate superconductors 23 , it thus implies that the Uemura relation may be a universal relation in strongly correlated superconductors in despite of whether the gap nodes at the charge-carrier Fermi surface exist or not.…”

“…As in the case of square-lattice superconductors 23 , the second term in the right-hand side refer to the contribution from the electron spin, and can be shown that…”

“…In this case, we need to impose boundary conditions for charge carriers, which can be done within the simplest specular reflection model 51,52 with a two-dimensional geometry of the SC plane. Following our previous discussions of the electromagnetic response in square-lattice superconductors 23,50 , the local magnetic field profile of triangular-lattice superconductors can be evaluated explicitly as, (34) and then the magnetic-field-penetration depth is obtained from this local-magnetic-field profile as,…”

“…The former results in the thermally activated (exponential) temperature dependence of the magnetic-field-penetration depth, whereas the latter one implies a power law behavior. For square-lattice superconductors, the Meissner effect has been studied experimentally 20,21 as well as theoretically 22,23 . In particular, the electromagnetic response in square-lattice superconductors has been discussed 23 based on the kinetic-energy-driven superconducting (SC) mechanism 24,25 , and the obtained results of the doping and temperature dependence of the magneticfield-penetration depth and superfluid density are well consistent with the experimental data observed on square-lattice superconductors 20,21 .…”

“…For square-lattice superconductors, the Meissner effect has been studied experimentally 20,21 as well as theoretically 22,23 . In particular, the electromagnetic response in square-lattice superconductors has been discussed 23 based on the kinetic-energy-driven superconducting (SC) mechanism 24,25 , and the obtained results of the doping and temperature dependence of the magneticfield-penetration depth and superfluid density are well consistent with the experimental data observed on square-lattice superconductors 20,21 . In triangular-lattice cobaltate superconductors, on the other hand, although the Meissner effect has been investigated by virtue of systematic studies using the muon-spin-rotation measurement technique 26,27 , the electromagnetic response has not been clarified starting from a microscopic SC theory, and no explicit calculations of the evolution of the superfluid density with doping and temperature has been made so far.…”