Manipulating Peierls Distortion in van der Waals NbOX₂ Maximizes Second-Harmonic Generation

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(30), P. 16828 - 16834

Published: July 19, 2023

Two-dimensional (2D) van der Waals (vdW) materials, featuring relaxed phase-matching conditions and highly tunable optical nonlinearity, endow them with potential applications in nanoscale nonlinear (NLO) devices. Despite significant progress, fundamental questions 2D NLO materials remain, such as how structural distortion affects second-order properties, which call for advanced regulation situ diagnostic tools. Here, by applying pressure to continuously tune the displacement of Nb atoms vdW NbOI2, we effectively modulate polarization achieve a 3-fold boost second-harmonic generation (SHG) at 2.5 GPa. By introducing Peierls parameter, λ, establish quantitative relationship between λ SHG intensity. Importantly, further demonstrate that enhancement can be achieved under ambient anionic substitution NbO(I1-xBrx)2 (x = 0-1) compounds, where chemical tailoring simulates effects on optimization. Consequently, NbO(I0.60Br0.40)2 0.17 exhibits giant over 2 orders magnitude higher than monolayer WSe2, reaching record-high value among reported materials. This work unambiguously demonstrates correlation property and, more broadly, opens new paths development manipulating structure distortions.

Language: Английский

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Electrically gated molecular thermal switch

Science, Journal Year: 2023, Volume and Issue: 382(6670), P. 585 - 589

Published: Nov. 2, 2023

Controlling heat flow is a key challenge for applications ranging from thermal management in electronics to energy systems, industrial processing, and therapy. However, progress has generally been limited by slow response times low tunability conductance. In this work, we demonstrate an electronically gated solid-state switch using self-assembled molecular junctions achieve excellent performance at room temperature. three-terminal device, continuously reversibly modulated electric field through carefully controlled chemical bonding charge distributions within the interface. The devices have ultrahigh switching speeds above 1 megahertz, on/off ratios conductance greater than 1300%, can be switched more million times. We anticipate that these advances will generate opportunities engineering systems circuit design.

Language: Английский

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Second Harmonic Generation Control in 2D Layered Materials: Status and Outlook

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(16)

Published: Jan. 4, 2024

Abstract Second harmonic generation (SHG) as an essential nonlinear optical effect, has gradually shifted its research trend toward the integration and miniaturization of photonic optoelectronic on‐chip devices in recent years. 2D layered materials (2DLMs) open up a new paradigm optics due to their large second‐order susceptibility, atomically thin structure, perfect phase‐matching. However, 2DLMs are facing bottleneck weak SHG conversion efficiency limit caused by short light–matter interaction lengths at nanoscale. Moreover, advances integrated based on rely continuing development novel strategies with tunable efficient responses. Here, this review provides comprehensive overview progress exploring highly responses 2DLMs. Various modulation enhancement for response extensively studied systematically discussed, which can be classified into two categories: symmetry breaking light‐matter enhancement. remaining challenges outlooks further extending realizing practical applications characteristics discussed.

Language: Английский

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Suppressed thermal transport in silicon nanoribbons by inhomogeneous strain

Nature, Journal Year: 2024, Volume and Issue: 629(8014), P. 1021 - 1026

Published: May 15, 2024

Language: Английский

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Actively and reversibly controlling thermal conductivity in solid materials

Physics Reports, Journal Year: 2024, Volume and Issue: 1058, P. 1 - 32

Published: Jan. 25, 2024

Language: Английский

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Antithermal Quenching Upconversion Luminescence via Suppressed Multiphonon Relaxation in Positive/Negative Thermal Expansion Core/Shell NaYF₄:Yb/Ho@ScF₃ Nanoparticles

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(10), P. 6530 - 6535

Published: Feb. 27, 2024

Thermal quenching (TQ) has been naturally entangling with luminescence since its discovery, and lattice vibration, which is characterized as multiphonon relaxation (MPR), plays a critical role. Considering that MPR may be suppressed under exterior pressure, we have designed core/shell upconversion (UCL) system of α-NaYF

Language: Английский

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Convergent thermal conductivity in strained monolayer graphene

Physical review. B./Physical review. B, Journal Year: 2024, Volume and Issue: 109(3)

Published: Jan. 17, 2024

The strain dependence of thermal conductivity (\ensuremath{\kappa}) in monolayer graphene, with reports enhancement, suppression, or even divergence, has been highly controversial. To address this open question, we have systematically investigated the effects tensile on \ensuremath{\kappa} graphene using exact solution Peierls-Boltzmann transport equation based first-principles interatomic force constants combined machine learning assisted molecular dynamics simulations. In contrast to previous studies, find that strained is convergent after considering four-phonon scattering, which dominant for long-wavelength flexural phonons because its much weaker frequency (${\ensuremath{\tau}}_{4}^{\ensuremath{-}1}\ensuremath{\propto}{\ensuremath{\omega}}^{\ensuremath{\beta}}$ \ensuremath{\beta} 2) compared three-phonon scattering case (${\ensuremath{\tau}}_{3}^{\ensuremath{-}1}\ensuremath{\propto}{\ensuremath{\omega}}^{\ensuremath{\beta}}$ > 2). Furthermore, exhibits nonmonotonic variations increasing up 8% due competition between phonon lifetime, group velocity, and heat capacity acoustic phonons. Our results deepen fundamental understanding offer insights tuning properties two-dimensional materials through engineering.

Language: Английский

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A MoS2/BAs heterojunction as photodetector

Materials Today Physics, Journal Year: 2024, Volume and Issue: 42, P. 101360 - 101360

Published: Feb. 8, 2024

Language: Английский

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Electron-Induced Nonmonotonic Pressure Dependence of the Lattice Thermal Conductivity of θ -TaN

Physical Review Letters, Journal Year: 2024, Volume and Issue: 132(11)

Published: March 15, 2024

Recent theoretical and experimental research suggests that $\ensuremath{\theta}$-TaN is a semimetal with high thermal conductivity ($\ensuremath{\kappa}$), primarily due to the contribution of phonons (${\ensuremath{\kappa}}_{\mathsf{ph}}$). By using first-principles calculations, we show nonmonotonic pressure dependence $\ensuremath{\kappa}$ $\ensuremath{\theta}$-TaN. ${\ensuremath{\kappa}}_{\mathsf{ph}}$ first increases until it reaches maximum at around 60 GPa, then decreases. This anomalous behavior consequence competing responses phonon-phonon phonon-electron interactions, in contrast known materials BAs BP, where caused by interplay between different scattering channels. Although TaN has phonon dispersion features similar ambient pressure, its response an overall stiffening branches takes place. Consequently, relevant weakens as increases. However, increased electronic density states near Fermi level, specifically emergence additional pockets surface high-symmetry L point Brillouin zone, leads substantial increase pressures, driving decrease ${\ensuremath{\kappa}}_{\mathrm{ph}}$. At intermediate pressures ($\ensuremath{\sim}20--70\text{ }\text{ }\mathrm{GPa}$), surpasses BAs. Our Letter provides deeper insight into transport semimetals metals relevant.

Language: Английский

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Ballistic Transport from Propagating Vibrational Modes in Amorphous Silicon Dioxide: Thermal Experiments and Atomistic-Machine Learning Modeling

Materials Today Physics, Journal Year: 2025, Volume and Issue: unknown, P. 101659 - 101659

Published: Jan. 1, 2025

Language: Английский

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