Giant enhancement of exciton radiative lifetime by ferroelectric polarization: The case of monolayer TiOCl${}_2$

Abstract

Exciton binding energy and lifetime are the two most important parameters controlling exciton dynamics, and the general consensus is that the larger the former the larger the latter. However our first-principles study of monolayer ferroelectric TiOCl${}_2$ shows that this is not always the case. We find that ferroelectric polarization tends to weaken exciton binding but enhance exciton lifetime. This stems from the different effects of the induced built-in electric field and structural distortion by the spontaneous polarization: the former always destabilizes or even dissociates the exciton while the latter leads to a relaxation of the selection rule and activates excitons that are otherwise not optically active. Their combined effect leads to a halving of the exciton binding energy but a substantial increase in lifetime by 40 times. Our results deepen the understanding of the interaction of light with ferroelectric materials and provide new insights into the use of ferroelectricity to control exciton dynamics.

References in corpus (24)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Atomically thin MoS2: A new direct-gap semiconductor
• Atomistic origins of high-performance in hybrid halide perovskite solar cells
• Tightly bound excitons in monolayer WSe2
• Yambo: an \textit{ab initio} tool for excited state calculations
• Many-body perturbation theory calculations using the yambo code
• Signatures of exciton condensation in a transition metal dichalcogenide
• Theory and it ab initio calculation of radiative lifetime of excitons in semiconducting carbon nanotubes
• Optical properties of graphene nanoribbons: the role of many-body effects
• Simple Screened Hydrogen Model of Excitons in Two-Dimensional Materials
• Dissociation of two-dimensional excitons in monolayer WSe2
• Twist Angle Dependent Interlayer Exciton Lifetimes in van der Waals Heterostructures
• Two-dimensional ferromagnetic-ferroelectric multiferroics in violation of the d0 rule
• Controlling excitons in an atomically thin membrane with a mirror
• Ab Initio Calculations of Exciton Radiative Lifetimes in Bulk Crystals, Nanostructures and Molecules
• Spin-Triplet Excitonic Insulator: The Case of Graphone
• Theory and Ab Initio Computation of the Anisotropic Light Emission in Monolayer Transition Metal Dichalcogenides
• Half Excitonic Insulator: A Single-Spin Bose-Einstein Condensate
• Realizing intrinsic excitonic insulator by decoupling exciton binding energy from the minimum band gap
• Excitonic Instability and Electronic Property of Two-dimensional AlSb Limit
• Understanding the origin of bandgap problem in transition and post-transition metal oxides
• Transition from band insulator to excitonic insulator via alloying Se into Monolayer TiS${}_3$: A Computational Study
• Optical signature for distinguishing between Mott-Hubbard, intermediate and charge-transfer insulators
• Electric field induced narrowing of exciton line width

Cited by in corpus (1)

• Electronic and Optical Properties of Ta${}_2$NiSe${}_5$ Monolayer: A First-principles Study