Related Experiment Video
Updated: Aug 2, 2025
Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures
Published on: December 5, 2015
Coulomb enhancement of high harmonic generation in monolayer transition metal dichalcogenides
Abstract:
High harmonic generation (HHG) in monolayer MoS2 is studied using fully microscopic many-body models based on the semiconductor Bloch equations and density functional theory. It is shown that Coulomb correlations lead to a dramatic enhancement of HHG. In particular, near the bandgap, enhancements of two orders of magnitude or more are observed for a wide range of excitation wavelengths and intensities. For excitation at excitonic resonances, strong absorption leads to spectrally broad sub-floors of the harmonics that is absent without Coulomb interaction. The widths of these sub-floors depend strongly on the dephasing time for polarizations. For times of the order of 10 fs the broadenings are comparable to the Rabi energies and reach one electronvolt at fields of approximately 50 MV/cm. The intensities of these contributions are approximately four to six orders below the peaks of the harmonics.
More Related Videos
08:50Preparation of Large-area Vertical 2D Crystal Hetero-structures Through the Sulfurization of Transition Metal Films for Device Fabrication
Published on: November 28, 2017
10:41Preparation of Liquid-exfoliated Transition Metal Dichalcogenide Nanosheets with Controlled Size and Thickness: A State of the Art Protocol
Published on: December 20, 2016
Related Concept Videos
02:58Crystal Field Theory - Octahedral Complexes
To explain the observed behavior of transition metal complexes (such as colors), a model involving electrostatic interactions between the electrons from the ligands and the electrons in the unhybridized d orbitals of the central metal atom has been developed. This electrostatic model is crystal field theory (CFT). It helps to understand, interpret, and predict the colors, magnetic behavior, and some structures of coordination compounds of transition metals.
CFT focuses on...
01:24Metal-Semiconductor Junctions
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The...
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...