Mechanisms of nonthermal destruction of the superconducting state and melting of the charge-density-wave state by femtosecond laser pulses

Abstract

The processes leading to nonthermal condensate vaporization and charge-density wave (CDW) melting with femtosecond laser pulses is systematically investigated in different materials. We find that vaporization is relatively slow (tau_v ~ 1 ps) and inefficient in superconductors, exhibiting a strong systematic dependence of the vaporization energy Uv on Tc. In contrast, melting of CDW order proceeds rapidly (tau_m = 50 ~ 200 fs) and more efficiently. A quantitative model describing the observed systematic behavior in superconductors is proposed based on a phonon-mediated quasi-particle (QP) bottleneck mechanism. In contrast, Fermi surface disruption by hot QPs is proposed to be responsible for CDW state melting.