The quasiparticle dynamics with different symmetry further investigated in the superconducting (SC) and normal state of the high-temperature superconductor Bi2Sr2CaCu2O8+δ (Bi2212) using optical pump-probe experiments with different light polarizations at different doping levels. The observation of distinct selection rules for SC excitations present in A1g and B1g symmetries, and for the pseudogap (PG) excitations present in A1g and B2g symmetries by the probe, and absence of any dependence on the pump beam polarization leads to the unequivocal conclusion of the existence of a spontaneous spatial symmetry breaking in the PG state not limited to the sample surface.
COBISS.SI-ID: 27968295
A remarkable change of the quasiparticle relaxation dynamics at the antiferromagnetic transition temperature in iron-based superconductors parent spin-density wave compounds AAs2Fe2 , (A=Ba, Sr, and Eu), observed previously by the near infrared probe, was systematically investigated by broad-band visible time resolved spectroscopy. Two different relaxation processes were identified. The behavior of the slower process, which is strongly sensitive to the magnetostructural transition, was analyzed in the framework of the relaxation-bottleneck model involving magnons. The results were also compared to recent time-resolved angular photoemission results and possible alternative assignment of the slower relaxation to the magnetostructural order parameter relaxation was discussed.
COBISS.SI-ID: 27689767