Spin-Mediated Energy of Cuprate Superconductors

Spin fluctuation in strong correlated systems give rise to superconductivity in cuprate superconductors. The correlation effects in copper oxide (Cu0₂) layers give rise to collective excitations in high- cuprates. Here, the energy of electron doped Niodium Cellenium Copper Oxide (Nd_2-xCe_xCuO₄ -NCCO) and Praseodymium Cellenium Copper Oxide (Pr2-xCexCuO4-PCCO) and hole doped Yitrium Barium Copper Oxide (YBa2CuO7-YBCO) and Lanthanum Strontium Copper Oxide (La2-xSrxCuO4-LSCO) within the Heisenberg-Hubbard-Holstein model by means of the Bogoliubov-Valatin Transformation (BVT) approach. The energy of the system is seen to be very low for T<185K and an exponential increase in the energy of the system at T>185K for the four cuprates. At T=T_c, there is transition of state from normal material to superconducting state and the energy at this particular point was determined to be…..