SFB Colloquium

The origin of the universal antinodal suppression of quasiparticles in the normal state of high-Tc superconducting (HTSC) copper oxides remains a lively debated issue. We combine table-top time-resolved optical and photoemission spectroscopies to obtain a comprehensive picture about the relaxation dynamics in strongly correlated copper oxides. In particular, we perform time-resolved extreme-ultra-violet (EUV) photoemission on a prototypical HTSC cuprate, Bi2212, to disclose the ultrafast dynamics of the antinodal states [1-2]. After photoinducing a non-thermal charge redistribution within the Cu and O orbitals, we observe the transient weakening of the antinodal quasiparticle suppression via the formation of additional states which relax back on the ~100 fs timescale. Our results suggest that the antinodal suppression of states stems from the correlation-driven freezing of the electrons moving along the Cu-O bonds, analogously to the Mott localization mechanism. Finally, we observe an ultrafast gaussian broadening of the O-2p states suggesting an intrinsic spatial inhomogeneity of the charge-transfer photo-excitation process.

[1] F. Cilento et al., Dynamics of correlation-frozen antinodal quasiparticles in superconducting cuprates, Science Advances 4, eaar1998 (2018)

[2] F. Cilento et al., Photo-enhanced antinodal conductivity in the pseudogap state of high-Tc cuprates, Nature Communications 5, 4353 (2014)