Ab Initio Simulation of Attosecond Transient Absorption Spectroscopy in Two-Dimensional Materials

• Main Authors: Shunsuke A. Sato, Hannes Hübener, Umberto De Giovannini, Angel Rubio
• Format: Article
• Language: English
• Published: MDPI AG 2018-09-01
• Series: Applied Sciences
• Subjects: attosecond transient absorption spectroscopy; time-dependent density functional theory; first-principles simulation
• Online Access: http://www.mdpi.com/2076-3417/8/10/1777

We extend the first-principles analysis of attosecond transient absorption spectroscopy to two-dimensional materials. As an example of two-dimensional materials, we apply the analysis to monolayer hexagonal boron nitride (h-BN) and compute its transient optical properties under intense few-cycle infrared laser pulses. Nonadiabatic features are observed in the computed transient absorption spectra. To elucidate the microscopic origin of these features, we analyze the electronic structure of h-BN with density functional theory and investigate the dynamics of specific energy bands with a simple two-band model. Finally, we find that laser-induced intraband transitions play a significant role in the transient absorption even for the two-dimensional material and that the nonadiabatic features are induced by the dynamical Franz–Keldysh effect with an anomalous band dispersion.