Local density of states in a d -wave superconductor with stripelike modulations and a strong impurity

Using an effective Hamiltonian with d-wave superconductivity (dSC) and competing antiferromagnetic (AF) interactions, we show that weak and one-dimensionally modulated dSC, spin density wave (SDW), and charge density wave (CDW) could coexist in the ground state configuration. With proper parameters, the SDW order exhibits a period of 8a, while for dSC and CDW orders the period is 4a. The local density of states (LDOS), which probes the behavior of quasiparticle excitations, is found to have the identical stripelike structure as those in dSC and CDW orders. The LDOS as a function of the bias voltage are showing two small bumps within the superconducting coherence peaks, a signature of the presence of stripes. When a strong impurity like Zn is placed in such a system, the LDOS at its nearest neighboring sites are suppressed at the zero bias by the local AF order and show a double-peak structure.