Role of spinon and spinon singlet pair excitations on phase transitions in $d-wave$ superconductors

摘要

We examine the roles of massless Dirac spinon and spin singlet pairexcitations on the phase transition in $d-wave$ superconductors. Although themassless spinon excitations in the presence of the spin singlet pairexcitations do not alter the nature of the phase transition at $T = 0$, thatis, the XY universality class, they are seen to induce an additional attractiveinteraction potential between vortices, further stabilizing vortex-antivortexpairs at low temperature for lightly doped high $T_c$ samples.