Naslov
Transient excitons at metal surfaces

Autori
Cui, Xuefeng ; Wang, Cong ; Argondizzo, Adam ; Garrett-Roe, Sean ; Gumhalter, Branko ; Petek, Hrvoje

Izvornik
Nature Physics (1745-2473) 10 (2014); 505-509

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, pismo, znanstveni

Ključne riječi
transient excitons; excitons at metal surfaces

Sažetak
Excitons, electron–hole pairs bound by the Coulomb potential, are the fundamental quasiparticles of coherent light–matter interaction relevant for processes such as photosynthesis and optoelectronics [1, 2, 3, 4, 5]. The existence of excitons in semiconductors is well established[2]. For metals, however, although implied by the quantum theory of the optical response, experimental manifestations of excitons are tenuous owing to screening of the Coulomb interaction taking place on timescales of a few femtoseconds[6, 7, 8]. Here we present direct evidence for the dominant transient excitonic response at a Ag(111) surface, which precedes the full onset of screening of the Coulomb interaction, in the course of a three-photon photoemission process with ∼15 fs laser pulses. During this transient regime, electron–hole pair Coulomb interactions introduce coherent quasiparticle correlations beyond the single-particle description of the optics of metals that dominate the multi-photon photoemission process on the timescale of screening at a Ag(111) surface

Izvorni jezik
Engleski

Znanstvena područja
Fizika

POVEZANOST RADA