Many-body theory of the optical conductivity of excitons and trions in two-dimensional materials

Rana, Farhan; Koksal, Okan; Manolatou, Christina

doi:10.1103/physrevb.102.085304

Cited by 48 publications

(99 citation statements)

References 30 publications

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“…Figure 5 c shows the energy splitting between

and

as a function of the gate voltage and the Fermi energy level. We found that the splitting between the two transitions increases linearly with the doping level of the device, as predicted and observed in previous literature for exciton and trion transitions [ 30 , 33 , 34 ], following the equation

where

is the splitting between exciton and trion transitions;

is the binding energy of

;

is the Fermi energy, which is proportional to the back-gate voltage; and c is the slope of the linear fit, predicted to have a value of

[ 33 ].…”

Section: Resultssupporting

confidence: 89%

The Low-Temperature Photocurrent Spectrum of Monolayer MoSe2: Excitonic Features and Gate Voltage Dependence

et al. 2022

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Two-dimensional transition metal dichalcogenides (2D-TMDs) are among the most promising materials for exploring and exploiting exciton transitions. Excitons in 2D-TMDs present remarkably long lifetimes, even at room temperature. The spectral response of exciton transitions in 2D-TMDs has been thoroughly characterized over the past decade by means of photoluminescence spectroscopy, transmittance spectroscopy, and related techniques; however, the spectral dependence of their electronic response is still not fully characterized. In this work, we investigate the electronic response of exciton transitions in monolayer MoSe2 via low-temperature photocurrent spectroscopy. We identify the spectral features associated with the main exciton and trion transitions, with spectral bandwidths down to 15 meV. We also investigate the effect of the Fermi level on the position and intensity of excitonic spectral features, observing a very strong modulation of the photocurrent, which even undergoes a change in sign when the Fermi level crosses the charge neutrality point. Our results demonstrate the unexploited potential of low‑temperature photocurrent spectroscopy for studying excitons in low-dimensional materials, and provide new insight into excitonic transitions in 1L-MoSe2.

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“…Figure 5 c shows the energy splitting between

and

where

is the splitting between exciton and trion transitions;

is the binding energy of

;

is the Fermi energy, which is proportional to the back-gate voltage; and c is the slope of the linear fit, predicted to have a value of

[ 33 ].…”

Section: Resultssupporting

confidence: 89%

The Low-Temperature Photocurrent Spectrum of Monolayer MoSe2: Excitonic Features and Gate Voltage Dependence

et al. 2022

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“…The error estimation is discussed in the ESI. † The influence of the many-body excitonic state, [34][35][36] which has traditionally been called trion, has been neglected as they are negligible at room temperature and intrinsic electron doping levels. 37,38 In fact, one single Lorentzian reproduces the static spectrum accurately, without the need of including a second Lorentzian to model the trion which is observed in low temperature photoluminescence experiments.…”

Section: Resultsmentioning

confidence: 99%

Ultrafast evolution of the complex dielectric function of monolayer WS₂ after photoexcitation

Calati

Zhu

et al. 2021

Phys. Chem. Chem. Phys.

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“…The large binding energy of excitons in TMDs as compared to other microcavity semiconductors such as quantum-wells [32][33][34], combined with the possibility to control the electron density in the different valleys, opens up exciting new venues to explore Bose-Fermi mixtures in a hybrid light-matter setting [35][36][37]. This has stimulated a number of studies regarding the properties electron-exciton mixtures and their coupling to light [38][39][40][41][42][43][44][45][46][47][48]. In particular, the emergence of new quasiparticles, the so-called Fermipolaron-polaritons have been observed [49].…”

Section: Introductionmentioning

confidence: 99%

Polaritons in an Electron Gas—Quasiparticles and Landau Effective Interactions

Bastarrachea-Magnani

Thomsen

Camacho-Guardián

et al. 2021

Atoms

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Two-dimensional semiconductors inside optical microcavities have emerged as a versatile platform to explore new hybrid light–matter quantum states. A strong light–matter coupling leads to the formation of exciton-polaritons, which in turn interact with the surrounding electron gas to form quasiparticles called polaron-polaritons. Here, we develop a general microscopic framework to calculate the properties of these quasiparticles, such as their energy and the interactions between them. From this, we give microscopic expressions for the parameters entering a Landau theory for the polaron-polaritons, which offers a simple yet powerful way to describe such interacting light–matter many-body systems. As an example of the application of our framework, we then use the ladder approximation to explore the properties of the polaron-polaritons. Furthermore, we show that they can be measured in a non-demolition way via the light transmission/reflection spectrum of the system. Finally, we demonstrate that the Landau effective interaction mediated by electron-hole excitations is attractive leading to red shifts of the polaron-polaritons. Our work provides a systematic framework to study exciton-polaritons in electronically doped two-dimensional materials such as novel van der Waals heterostructures.

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Many-body theory of the optical conductivity of excitons and trions in two-dimensional materials

Cited by 48 publications

References 30 publications

The Low-Temperature Photocurrent Spectrum of Monolayer MoSe2: Excitonic Features and Gate Voltage Dependence

The Low-Temperature Photocurrent Spectrum of Monolayer MoSe2: Excitonic Features and Gate Voltage Dependence

Ultrafast evolution of the complex dielectric function of monolayer WS₂ after photoexcitation

Polaritons in an Electron Gas—Quasiparticles and Landau Effective Interactions

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Many-body theory of the optical conductivity of excitons and trions in two-dimensional materials

Cited by 48 publications

References 30 publications

The Low-Temperature Photocurrent Spectrum of Monolayer MoSe2: Excitonic Features and Gate Voltage Dependence

The Low-Temperature Photocurrent Spectrum of Monolayer MoSe2: Excitonic Features and Gate Voltage Dependence

Ultrafast evolution of the complex dielectric function of monolayer WS2 after photoexcitation

Polaritons in an Electron Gas—Quasiparticles and Landau Effective Interactions

Contact Info

Product

Resources

About

Ultrafast evolution of the complex dielectric function of monolayer WS₂ after photoexcitation