專題演講

2020/11/05(Thu)     11:00 -12:00    五樓第一會議室5th Floor(1st meeting room)

Title

Laser-based photoelectron spectroscopy on correlated electron pairs in solids

Speaker

Dr. Cheng-Tien Chiang

Institute of Atomic and Molecular Sciences, Academia Sinica

Abstract

The interaction between electrons in solids has been a major research topic since the beginning of quantum mechanics. With the recent development of angle-resolved photoelectron spectroscopy (ARPES) as well as scanning tunneling spectroscopy (STS), there have been intensive studies of electron-electron interaction in quantum materials. Aiming at the quantitative estimation of the energy- and momentum-dependent self-energy of quasiparticles, pioneering ARPES and STS experiments have revealed the signatures of electron-electron interaction as well as electron-phonon coupling in great detail. However, in the state-of-the-art ARPES and STS experiments only one electron can be detected explicitly. In order to directly analyze two interacting electrons in solids, double photoemission (DPE) spectroscopy has been developed progressively [1,2]. In DPE, a pair of electrons is emitted upon the absorption of one single photon [3], and each of the two electrons within a pair can be analyzed explicitly. In this talk, DPE experiments on paradigmatic metallic systems Ag(001) and Cu(111) will be presented [4]. These results will be compared with DPE on the strongly correlated system NiO and discussed in terms of electron correlation. (Abstract)