Nonlinear optics in the electron-hole continuum in 2D semiconductors: two-photon transition, second harmonic generation and valley current injection
arXiv:1903.05588
Abstract
We investigate two-photon transitions to the electron-hole scattering continuum in monolayer transition-metal dichalcogenides, and identify two contributions to this nonlinear optical process with opposite circularly polarized valley selection rules. In the non-interacting limit, the competition between the two contributions leads to a crossover of the selection rule with the increase of the two-photon energy. With the strong Coulomb interaction between the electron and hole, the two contributions excite electron-hole scattering states in orthogonal angular momentum channels, while the strength of the transition can be substantially enhanced by the interaction. Based on this picture of the two-photon transition, the second harmonic generation (SHG) in the electron-hole continuum is analyzed, where the Coulomb interaction is shown to greatly alter the relative strength of different cross-circular polarized SHG processes. Valley current injection by the quantum interference of one-photon and two-photon transition is also investigated in the presence of the strong Coulomb interaction, which significantly enhances the injection rate.
References in corpus (29)
- Atomically thin MoS2: A new direct-gap semiconductor
- Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
- Control of valley polarization in monolayer MoS2 by optical helicity
- Valley polarization in MoS2 monolayers by optical pumping
- Observation of tightly bound trions in monolayer MoS2
- MoS_2 as an ideal material for valleytronics: valley-selective circular dichroism and valley Hall effect
- Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
- Excitons in atomically thin transition metal dichalcogenides
- The Valley Hall Effect in MoS2 Transistors
- Optical Spectrum of MoS: Many-body Effects and Diversity of Exciton States
- Electrical Control of Two-Dimensional Neutral and Charged Excitons in a Monolayer Semiconductor
- Optical Generation of Excitonic Valley Coherence in Monolayer WSe2
- Direct observation of the transition from indirect to direct bandgap in atomically thin epitaxial MoSe2
- Tightly bound excitons in monolayer WSe2
- Valley Dependent Optoelectronics from Inversion Symmetry Breaking
- Probing Excitonic Dark States in Single-layer Tungsten Disulfide
- Quasiparticle band structures and optical properties of strained monolayer MoS2 and WS2
- Observation of Intense Second Harmonic Generation from MoS Atomic Crystals
- Second harmonic microscopy of monolayer MoS2
- Electronic structures and theoretical modelling of two-dimensional group-VIB transition metal dichalcogenides
- Non-linear Optical Spectroscopy of Excited Exciton States for Efficient Valley Coherence Generation in WSe2 Monolayers
- Electrical Control of Second-Harmonic Generation in a WSe2 Monolayer Transistor
- Valley excitons in two-dimensional semiconductors
- Direct Measurement of Exciton Valley Coherence in Monolayer WSe
- Second Harmonic Generation in h-BN and MoS monolayers: the role of electron-hole interaction
- Bright and dark singlet excitons via linear and two-photon spectroscopy in monolayer transition-metal dichalcogenides
- Intrinsic exciton states mixing and non-linear optical properties in transition metal dichalcogenide monolayers
- Excitonic effects on the two-color coherent control of interband transitions in bulk semiconductors
- Optical selection rules for excitonic Rydberg series in the massive Dirac cones of hexagonal 2D materials