Tightly bound excitons in two-dimensional semiconductors with a flat valence band

Abstract

This theoretical paper offers an explicit expression for the binding energy of excitons in a two-dimensional semiconductor with a flat valence band. The formula has been derived quasiclassically assuming that the exciton is tightly bound; i.e., its ground-state radius is determined by the intrinsic polarizability of the semiconductor rather than by the dielectric properties of the environment. The model is relevant to a few two-dimensional semiconductors discovered recently, including distorted 1T-TiSe${}_2$, with a supposedly unstable electronic ground state. The valence band flatness reduces the exciton binding energy, which also may have an effect on the phase transition to an excitonic insulator.

arXiv comment7 pages, published in Phys. Rev. B with minor corrections

References in corpus (31)

• 2D materials and van der Waals heterostructures
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Excitons in atomically thin transition metal dichalcogenides
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Tightly bound excitons in monolayer WSe2
• Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
• Realization of Quantum Spin Hall State in Monolayer 1T'-WTe2
• Exciton Binding Energy of Monolayer WS2
• Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane
• Evidence for an excitonic insulator phase in 1T-TiSe${}_2$
• Exciton Diamagnetic Shifts and Valley Zeeman Effects in Monolayer WS${}_2$ and MoS${}_2$ to 65 Tesla
• Measurement of high exciton binding energy in the monolayer transition-metal dichalcogenides WS2 and WSe2
• Binding energies of exciton complexes in transition metal dichalcogenides and effect of dielectric environment
• Excitons in van der Waals heterostructures: The important role of dielectric screening
• Probing the influence of dielectric environment on excitons in monolayer WSe2: Insight from high magnetic fields
• Atomic Collapse and Quasi-Rydberg States in Graphene
• Analytical approach to excitonic properties of MoS2
• Band Structure and Optical Transitions in Atomic Layers of Hexagonal Gallium Chalcogenides
• Gate-Tuned Spontaneous Exciton Insulator in Double-Quantum Wells
• Ultrafast Electronic Band Gap Control in an Excitonic Insulator
• Excitons in anisotropic 2D semiconducting crystals
• Exciton band structure in two-dimensional materials
• Tunable Excitons in Biased Bilayer Graphene
• Stable charge density wave phase in a 1T-TiSe${}_2$ monolayer
• Manipulating charge-density-wave in monolayer $1T$-TiSe${}_2$ by strain and charge doping: A first-principles investigation
• Reproduction of the charge density wave phase diagram in $1T$-${\mathrm{TiSe}}_2$ exposes its excitonic character
• Realizing intrinsic excitonic insulator by decoupling exciton binding energy from the minimum band gap
• Model Prediction of Self-Rotating Excitons in Two-Dimensional Transition-Metal Dichalcogenides
• Measure of Diracness in two-dimensional semiconductors
• Can freestanding Xene monolayers behave as excitonic insulators?

Cited by in corpus (8)

• Collective Excitations in 2D Materials
• Control of excitonic absorption by thickness variation in few-layer GaSe
• Generalized scaling law for exciton binding energy in two-dimensional materials
• Crossover from weakly indirect to direct excitons in atomically thin films of InSe
• Valley-contrasting interband transitions and excitons in symmetrically biased dice model
• Interlayer excitonic insulator in two-dimensional double-layer semiconductor junctions: An explicitly solvable model
• Exciton Binding Energies in 2D Materials: Insights from Braneworld Physics
• High conductivity from cross-band electron pairing in flat-band systems