Self-consistent screening enhances the stability of the nonequilibrium excitonic insulator phase

Perfetto, Enrico; Marini, Andrea; Stefanucci, Gianluca

doi:10.1103/physrevb.102.085203

Cited by 13 publications

(14 citation statements)

References 73 publications

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“…We have recently shown [166,51,168] that after pumping the system is temporarily left in a BCS-like superfluid composed by a macroscopic number of excitons having a finite and oscillating polarization. Below we briefly discuss how to calculate the explicit wave-function of this superfluid since it is useful to predict the corresponding tr-ARPES spectrum.…”

Section: Excitonic Signatures In the Coherent Regime Of The Model Systemmentioning

confidence: 99%

“…The latter corresponds to the removal of an electron from the excitonic superfluid. As a function of the momentum, the exciton structure forms a side-band which is a replica of the valence band, shifted upward by [166,51]. The spectral weight of the side-band is proportional to the carrier density , and to the square modulus of the exciton wave-function | | 2 .…”

Section: Excitonic Signatures In the Coherent Regime Of The Model Systemmentioning

confidence: 99%

“…The photocurrent of a TR-ARPES experiment is generated by a probe pulse impinging the system. The spectrum depends on the intensity and frequency of the pump excitation, on the delay between pump and probe as well as on the duration of the probe [51]. Therefore TR-ARPES provides a unique tool to reveal different excitation and in particular to characterize the nature of what is generally defined an "exciton".…”

Section: Introductionmentioning

confidence: 99%

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Coherence and de-coherence in the Time-Resolved ARPES of realistic materials: an ab-initio perspective

Marini,

Perfetto,

Stefanucci

2021

Preprint

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Coherence and de-coherence are the most fundamental steps that follow the initial photo-excitation occurring in typical P&p experiments. Indeed, the initial external laser pulse transfers coherence to the system in terms of creation of multiple electronhole pairs excitation. The excitation concurs both to the creation of a finite carriers density and to the appearance of induced electromagnetic fields. The two effects, to a very first approximation, can be connected to the simple concepts of populations and oscillations. The dynamics of the system following the initial photo-excitation is, thus, entirely dictated by the interplay between coherence and de-coherence. This interplay and the de-coherence process itself, is due to the correlation effects stimulated by the photo-excitation. Single-particle, like the electron-phonon, and two-particles, like the electron-electron, scattering processes induce a complex dynamics of the electrons that, in turn, makes the description of the correlated and photo-excited system in terms of pure excitonic and/or carriers populations challenging. Contents 1 Introduction3

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Section: Excitonic Signatures In the Coherent Regime Of The Model Systemmentioning

confidence: 99%

Section: Excitonic Signatures In the Coherent Regime Of The Model Systemmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Coherence and de-coherence in the Time-Resolved ARPES of realistic materials: an ab-initio perspective

Marini,

Perfetto,

Stefanucci

2021

Preprint

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show abstract

“…Although the concept has been known for almost 60 years, to date compelling experimental evidence of the excitonic insulator is still missing. Since the EI phase is predicted to host many novel properties, such as superfluidity 3,4 , excitonic hightemperature superconductivity 5,6 , and exciton condensation, breakthroughs in finding this new class of insulators has attracted great attention over the last decades [6][7][8][9][10][11] .…”

Section: Introductionmentioning

confidence: 99%

Excitonic insulator states in molecular functionalized atomically-thin semiconductors

Christiansen¹,

Selig²,

Rossi³

et al. 2021

Preprint

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The excitonic insulator is an elusive electronic phase exhibiting a correlated excitonic ground state. Materials with such a phase are expected to have intriguing properties such as excitonic high-temperature superconductivity. However, compelling evidence on the experimental realization is still missing. Here, we theoretically propose hybrids of two-dimensional semiconductors functionalized by organic molecules as prototypes of excitonic insulators, with the exemplary candidate WS2-F6TCNNQ. This material system exhibits an excitonic insulating phase at room temperature with a ground state formed by a condensate of interlayer excitons. To address an experimentally relevant situation, we calculate the corresponding phase diagram for the important parameters: temperature, gap energy, and dielectric environment. Further, to guide future experimental detection, we show how to optically characterize the different electronic phases via far-infrared to terahertz (THz) spectroscopy.

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“…, where Y k is the exciton wavefunction [29,30,54,56,57]. We have recently shown that for small excited densities the coherent exciton superfluid is not able to screen the Coulomb interaction [58]. As a consequence the e-h attraction is not reduced and excitons survive < l a t e x i t s h a 1 _ b a s e 6 4 = " t s u Q R y / + 7 U 0 8 K 7 w x v 3 B f q J z l 6 L w = " for long time.…”

mentioning

confidence: 99%

Real-time GW: Toward an ab initio description of the ultrafast carrier and exciton dynamics in two-dimensional materials

Perfetto,

Pavlyukh,

Stefanucci

2021

Preprint

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Self-consistent screening enhances the stability of the nonequilibrium excitonic insulator phase

Cited by 13 publications

References 73 publications

Coherence and de-coherence in the Time-Resolved ARPES of realistic materials: an ab-initio perspective

Coherence and de-coherence in the Time-Resolved ARPES of realistic materials: an ab-initio perspective

Excitonic insulator states in molecular functionalized atomically-thin semiconductors

Real-time GW: Toward an ab initio description of the ultrafast carrier and exciton dynamics in two-dimensional materials

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