Ultrafast carrier-coupled interlayer contraction, coherent intralayer motions, and phonon thermalization dynamics of black phosphorus

Abstract

Black phosphorus (BP) exhibits highly anisotropic properties and dynamical behavior that are unique even among two-dimensional and van der Waals (vdW) layered materials. Here, we show that an interlayer lattice contraction and concerted, symmetric intralayer vibrations take place concurrently within few picoseconds following the photoinjection and relaxation of carriers, using ultrafast electron diffraction in the reflection geometry to probe the out-of-plane motions. A strong coupling between the photocarriers and BP's puckered structure, with the alignment of the electronic band structure, is at work for such directional atomic motions without a photoinduced phase transition. Three temporal regimes can be identified for the phonon thermalization dynamics where a quasi-equilibrium without anisotropy is reached in about 50 ps, followed by propagation of coherent acoustic phonons and heat diffusion into the bulk. The early-time out-of-plane dynamics reported here have important implications for single- and few-layer BP and other vdW materials with strong electronic-lattice correlations.

16 pages, 5 figures

References in corpus (7)

• Layer-dependent Band Alignment and Work Function of Few-Layer Phosphorene
• Dynamical Evolution of Anisotropic Response in Black Phosphorus under Ultrafast Photoexcitation
• Direct observation of optically induced transient structures in graphite using ultrafast electron crystallography
• Non-equilibrium Band Broadening, Gap Renormalization and Band Inversion in Black Phosphorus
• Anisotropic Charge Carrier and Coherent Acoustic Phonon Dynamics of Black Phosphorus Studied by Transient Absorption Microscopy
• Ultrafast carrier-lattice interactions and interlayer modulations of Bi2Se3 by X-ray free electron laser diffraction
• Excitons in bulk black phosphorus evidenced by photoluminescence at low temperature

Cited by in corpus (5)

• Strong Coupling of Self-Trapped Excitons to Acoustic Phonons in Bismuth Perovskite ${\text{Cs}}_3{\text{Bi}}_2{\text{I}}_9$
• Impacts of Hot Electron Diffusion, Electron-Phonon Coupling, and Surface Atoms on Metal Surface Dynamics Revealed by Reflection Ultrafast Electron Diffraction
• Cross-Examination of Photoinitiated Carrier and Structural Dynamics of Black Phosphorus at Elevated Fluences
• Low-frequency interlayer phonon dynamics and photoinduced terahertz absorption in black phosphorus
• Direct Observation of Energy Transport Dynamics and High Thermal Conductance across Single Solid-Molecule Junctions