We identify direct-transition photoemission peaks from the bulk valence bands of Si in energy- and momentum-resolved photoemission from Si(111)-(7×7) using polarized 6-eV laser light. Time-resolved study of spectral line shapes of the peaks under interband excitation by 2-eV femtosecond-laser pulses shows the ultrafast transient spectral-width broadening and its recovery associated with a low-energy peak shift. The changes reveal the dynamics of screening effects by electron-hole plasma, hot-hole relaxation, and band renormalization in photoexcited Si, showing strong many-body effects in relaxation at excitation density less than 1018cm-3.
|ジャーナル||Physical Review B|
|出版ステータス||Published - 2018 1月 3|
ASJC Scopus subject areas