Critical assessment of G0W0 calculations for 2D materials: the example of monolayer MoS2

npj Computational Materials, Год журнала: 2024, Номер 10(1)

Опубликована: Апрель 18, 2024

Two-dimensional (2D) materials combine many fascinating properties that make them more interesting than their three-dimensional counterparts for a variety of applications. For example, 2D exhibit stronger electron-phonon and electron-hole interactions, energy gaps effective carrier masses can be easily tuned. Surprisingly, published band several obtained with the $GW$ approach, state-of-the-art in electronic-structure calculations, are quite scattered. The details these such as underlying geometry, starting point, inclusion spin-orbit coupling, treatment Coulomb potential critically determine how accurate results are. Taking monolayer MoS$_2$ representative material, we employ linearized augmented planewave + local orbital method to systematically investigate all aspects affect quality $G_0W_0$ also provide summary literature data. We conclude best overall agreement experiments coupled-cluster calculations is found HSE06 point including truncated potential, an analytical singularity at $q=0$.

Язык: Английский

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Sub-bandgap charge harvesting and energy up-conversion in metal halide perovskites: ab initio quantum dynamics

npj Computational Materials, Год журнала: 2025, Номер 11(1)

Опубликована: Янв. 11, 2025

Metal halide perovskites (MHPs) exhibit unusual properties and complex dynamics. By combining ab initio time-dependent density functional theory, nonadiabatic molecular dynamics machine learning, we advance quantum simulation to nanosecond timescale demonstrate that large fluctuations of MHP defect energy levels extend light absorption longer wavelengths enable trapped charges escape into bands. This allows low photons contribute photocurrent through up-conversion. Deep can become shallow transiently vice versa, altering the traditional classification deep. While fluctuate more in MHPs than semiconductors, some levels, e.g., Pb interstitials, remain far from band edges, acting as charge recombination centers. Still, many defects deemed detrimental based on static structures, are fact benign The extended harvesting up-conversion provide strategies for design novel solar, optoelectronic, information devices.

Язык: Английский

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Defect-Enhanced Exciton–Exciton Annihilation in Monolayer Transition Metal Dichalcogenides at High Exciton Densities

ACS Photonics, Год журнала: 2021, Номер 8(9), С. 2770 - 2780

Опубликована: Авг. 31, 2021

The exciton–exciton annihilation (EEA) process easily occurs in monolayer transition metal dichalcogenides (TMDs) because of the strong Coulomb interaction and quantum confinement effect, which enhance many-body excitons. This can affect performance optoelectronic devices. It is crucial to examine effect defect states on EEA determine whether it comparable that at low excitation intensities, particularly when applied laser devices a high exciton density. In this study, femtosecond transient absorption spectroscopy was used explore four types CVD-grown TMDs (i.e., WS2, WSe2, MoS2, MoSe2). We demonstrated defect-assisted local excitons enhanced plays key role relaxation densities approximately 1012 cm–2 below Mott density 1013 cm–2. measured rates for MoSe2, MoS2 were 0.016, 0.026, 0.049, 0.102 cm2/s, respectively, implying as increase TMDs. Our results provide profound insight into densities.

Язык: Английский

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Ultrafast Charge Transfer and Delayed Recombination in Graphitic-CN/WTe₂ van der Waals Heterostructure: A Time Domain Ab Initio Study

The Journal of Physical Chemistry Letters, Год журнала: 2022, Номер 13(34), С. 7898 - 7905

Опубликована: Авг. 18, 2022

In search of an efficient solar energy harvester, we herein performed a time domain density functional study coupled with nonadiabatic molecular dynamics (NAMD) simulation to gain atomistic insight into the charge carrier graphitic carbon nitride (g-CN)-tungsten telluride (WTe2) van der Waals heterostructure. Our NAMD predicted ultrafast electron (589 fs) and hole-transfer (807 in g-CN/WTe2 heterostructure delayed electron-hole recombination process (2.404 ns) as compared that individual g-CN (3 ps) WTe2 (0.55 monolayer. The transfer is due strong electron-phonon coupling during charge-transfer while comparatively weak coupling, sufficient band gap, lower (NAC), fast decoherence slow down process. results exciton relaxation are valuable for insightful understanding designing photovoltaic devices based on organic-inorganic 2D heterostructures.

Язык: Английский

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Spin-orbit coupling induced demagnetization in Ni: Ab initio nonadiabatic molecular dynamics perspective

Physical review. B./Physical review. B, Год журнала: 2022, Номер 105(8)

Опубликована: Фев. 24, 2022

Spin-orbit coupling (SOC), which can induce spin flip during the relaxation of photoexcited charge carrier, plays a crucial role in dynamics. In this work, we have used time-domain ab initio nonadiabatic molecular dynamics (NAMD) method to study SOC induced ultrafast demagnetization Ni at $300\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. The spin-diabatic representation using spin-polarized Kohn-Sham (KS) basis sets and spin-adiabatic spinor been applied, both them achieve with timescale around $100\phantom{\rule{0.16em}{0ex}}\mathrm{fs}$. suggests picture that electron-phonon (EPC) provides direct energy channel among same-spin states, while flip. After photoexcitation, it is found spin-minority electrons relax states rather than opposite-spin since EPC larger by one order magnitude. By contrast, for spin-majority electrons, occurs there are no empty as electron acceptor above Fermi level. different pathways demagnetization. an Elliott-Yafet spin-phonon scattering picture. reduction magnetic moment may magnon drive further NAMD simulation critical angle understand how affect process Ni.

Язык: Английский

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Ultrafast and Nanoscale Energy Transduction Mechanisms and Coupled Thermal Transport across Interfaces

ACS Nano, Год журнала: 2023, Номер 17(15), С. 14253 - 14282

Опубликована: Июль 17, 2023

The coupled interactions among the fundamental carriers of charge, heat, and electromagnetic fields at interfaces boundaries give rise to energetic processes that enable a wide array technologies. energy transduction these results in thermal dissipation surfaces, often quantified by boundary resistance, thus driving functionalities modern nanotechnologies are continuing provide transformational benefits computing, communication, health care, clean energy, power recycling, sensing, manufacturing, name few. It is purpose this Review summarize recent works have been reported on ultrafast nanoscale heat transfer mechanisms across when different couple near or interfaces. We review solids, liquids, gasses, plasmas drive resulting interfacial temperature gradients due momentum coupling various combinations electrons, vibrons, photons, polaritons (plasmon phonon polaritons), molecules. These transport with involve relatively research, thus, several opportunities exist further develop nascent fields, which we comment throughout course Review.

Язык: Английский

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Real-Time GW-Ehrenfest-Fan-Migdal Method for Nonequilibrium 2D Materials

Nano Letters, Год журнала: 2023, Номер 23(15), С. 7029 - 7036

Опубликована: Июль 26, 2023

Quantum simulations of photoexcited low-dimensional systems are pivotal for understanding how to functionalize and integrate novel two-dimensional (2D) materials in next-generation optoelectronic devices. First-principles predictions extremely challenging due the simultaneous interplay light–matter, electron–electron, electron–nuclear interactions. We here present an advanced ab initio many-body method that accounts quantum coherence non-Markovian effects while treating electrons nuclei on equal footing, thereby preserving fundamental conservation laws like total energy. The impact this advancement is demonstrated through real-time complex multivalley dynamics a molybdenum disulfide (MoS2) monolayer pumped above gap. Within single framework, we provide parameter-free description coherent-to-incoherent crossover, elucidating role microscopic collective excitations dephasing thermalization processes.

Язык: Английский

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Quantum interference between dark-excitons and zone-edged acoustic phonons in few-layer WS2

Nature Communications, Год журнала: 2023, Номер 14(1)

Опубликована: Янв. 6, 2023

Fano resonance which describes a quantum interference between continuum and discrete states, provides unique method for studying strongly interacting physics. Here, we report dark excitons zone-edged acoustic phonons in few-layer WS2 by using the resonant Raman technique. The with large momentum at M-point of Brillouin zone exciton states related to optically forbidden transition K Q valleys are coupled exciton-phonon interactions. We observe rich behaviors across layers modes defined an asymmetry-parameter q: including constructive two mirrored asymmetry peaks (weak coupling, q > 1 < - 1), destructive dip (strong ∣q∣ 1). Our results provide new insight into two-dimensional semiconductors, where such interferences play key role their transport, optical, thermodynamic properties.

Язык: Английский

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Ultrafast Coherent Exciton Couplings and Many-Body Interactions in Monolayer WS₂

Nano Letters, Год журнала: 2024, Номер 24(26), С. 8117 - 8125

Опубликована: Июнь 20, 2024

Transition metal dichalcogenides (TMDs) are quantum confined systems with interesting optoelectronic properties, governed by Coulomb interactions in the monolayer (1L) limit, where strongly bound excitons provide a sensitive probe for many-body interactions. Here, we use two-dimensional electronic spectroscopy (2DES) to investigate and their dynamics 1L-WS

Язык: Английский

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Enhanced thermodynamic stability and carrier lifetime in BF4 -doped wide-band-gap perovskite solar cells

Physical review. B./Physical review. B, Год журнала: 2024, Номер 110(4)

Опубликована: Июль 23, 2024

Язык: Английский

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