Photo-excitation band-structure engineering of 2H-NbSe${}_2$ probed by time- and angle-resolved photoemission spectroscopy

Abstract

We investigated the nonequilibrium electronic structure of 2H-NbSe${}_2$ by time- and angle-resolved photoemission spectroscopy. We find that the band structure is distinctively modulated by strong photo-excitation, as indicated by the unusual increase in the photoelectron intensities around E${}_F$. In order to gain insight into the observed photo-induced electronic state, we performed DFT calculations with modulated lattice structures, and found that the variation of the Se height from the Nb layer results in a significant change in the effective mass and band gap energy. We further study the momentum-dependent carrier dynamics. The results suggest that the relaxation is faster at the K-centered Fermi surface than at the $\Gamma$-centered Fermi surface, which can be attributed to the stronger electron-lattice coupling at the K-centered Fermi surface. Our demonstration of band structure engineering suggests a new role for light as a tool for controlling the functionalities of solid-state materials.

arXiv comment7 pages, 5 figures

References in corpus (7)

• Ultrafast switching to a stable hidden topologically protected quantum state in an electronic crystal
• Enhanced superconductivity in atomically thin TaS2
• Photo-induced semimetallic states realised in electron-hole coupled insulators
• Band-dependent Quasiparticle Dynamics in Single Crystals of the Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ Superconductor Revealed by Pump-Probe Spectroscopy
• Photo-induced Superconducting State with Long-lived Disproportionate Band Filling in FeSe
• Antiphase Fermi-surface modulations accompanying displacement excitation in a parent compound of iron-based superconductors
• Ultrafast dynamics in normal and Charge Density Wave phase of 2H-NbSe2

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• Stacking of charge-density waves in 2H-NbSe${}_2$ bilayers
• Machine learning model for efficient nonthermal tuning of the charge density wave in monolayer NbSe${}_2$