Coulomb potential screening via charged carriers and charge-neutral dipoles/excitons in two-dimensional case

Abstract

With the shrinking of dimensionality, Coulomb interactions play a distinct role in two-dimensional (2D) semiconductors owing to the reduced dielectric screening in the out-of-plane direction. Apart from dielectric screening, free charge carriers and/or dipoles can also make a non-negligible contribution to Coulomb interaction. While the Thomas-Fermi model is effective in describing charge carrier screening in three dimensions, the extent of screening to two dimensions resulting from charge carriers and charge-neutral dipoles remains quantitatively unclear. Herein, we present an analytical solution based on linear response theory, offering a comprehensive depiction of the Coulomb screened potential in both 2D and 3D systems, where screening effects from both charge carriers and charge-neutral dipoles are addressed. Our work provides a useful and handy tool for directly analysing and evaluating Coulomb interaction strength in atomically thin materials, particularly in the context of electronic and optoelectronic engineering. As a demonstration, we utilized the derived modified Coulomb potential for the exciton system in 2D semiconductors to estimate the exciton binding energy variation arising from the exciton density fluctuation and temperature-dependent exciton polarizability, yielding excellent agreement with the computational and experimental findings.

References in corpus (20)

• Atomically thin MoS2: A new direct-gap semiconductor
• Exciton Binding Energy and Nonhydrogenic Rydberg Series in Monolayer WS2
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Moiré Excitons in Van der Waals Heterostructures
• Signatures of moiré-trapped valley excitons in MoSe${}_2$/WSe${}_2$ heterobilayers
• Observation of Moiré Excitons in WSe2/WS2 Heterostructure Superlattices
• Probing Excitonic Dark States in Single-layer Tungsten Disulfide
• Exciton Binding Energy of Monolayer WS2
• Dielectric screening in two-dimensional insulators: Implications for excitonic and impurity states in graphane
• Abundance of correlated insulating states at fractional fillings of WSe${}_2$/WS${}_2$ moiré superlattices
• Direct imaging of the band profile in single layer $Mo{S}_2$ on graphite: quasiparticle energy gap, metallic edge states and edge band bending
• Enhanced superconductivity in atomically thin TaS2
• Screening and Many-Body Effects in Two-Dimensional Crystals: Monolayer MoS${}_2$
• Revealing exciton masses and dielectric properties of monolayer semiconductors with high magnetic fields
• How dielectric screening in two-dimensional crystals affects the convergence of excited-state calculations: Monolayer MoS${}_2$
• Dielectric Screening by 2D Substrates
• Evidence for Exciton Crystals in a 2D Semiconductor Heterotrilayer
• Breakdown of the static approximation for free carrier screening of excitons in monolayer semiconductors
• Effects of Two-Dimensional Material Thickness and Surrounding Dielectric Medium on Coulomb Interactions and Excitons
• Exciton-exciton Interaction in Monolayer MoSe${}_2$ from Mutual Screening of Coulomb Binding