Speaker
Description
Electronic band structure and wavefunction determine the topology of a specific material. The signature of topology has been observed by various physical quantities like anomalous hall current, high-harmonic generation, circular dichroism, etc. Here, we theoretically present a new fingerprint of topology through the photoemission delay, which manifests the microscopic dynamics of the quantum phase. The photoemission delay is analytically obtained by the second-order time-dependent perturbation theory for two-photon dynamics in the monolayer Haldane model. Resultant analytic calculations show that a photoelectron undergoing laser-induced interband transition has an attosecond scale photoemission delay, which is agreed with our numerical simulation of the attosecond streaking method. Moreover, it is analytically found that the quantum coherence between the valence and conduction paths of a photoelectron causes an interference-induced delay, which delivers the information of Berry curvature.
