相关论文: Efficient excitation of nonlinear phonons via chir…
We have observed a softening of phonons and a structural phase transition in a superconducting Ba0.59K0.41BiO3 (Tc = 31 K) single crystal using elastic and inelastic neutron scattering measurements. The soft phonon occurs for the [111]…
The origins of enhanced piezoelectric coupling along nonpolar crystallographic directions in ferroelectric BaTiO3 are investigated using in situ neutron spectroscopy. It is observed that an electric field applied away from the equilibrium…
We present a microscopic theory for ultrafast control of solids with high-intensity terahertz frequency optical pulses. When resonant with selected infrared-active vibrations, these pulses transiently modify the crystal structure and lead…
Ultrafast electron-phonon relaxation dynamics in graphene hides many distinct phenomena, such as hot phonon generation, dynamical Kohn anomalies, and phonon decoupling, yet still remains largely unexplored. Here, we unravel intricate…
Complex systems are a proving ground for fundamental interactions between components and their collective emergent phenomena. Through intricate design, integrated photonics offers intriguing nonlinear interactions that create new patterns…
We use molecular dynamics simulations with machine-learned atomistic force fields to simulate photoexcitation of BaTiO3 by a femtosecond laser pulse whose photon energy exceeds the optical gap. We demonstrate selective displacive excitation…
Nonlinear optical signals in optically driven quantum systems can reveal coherences and thereby open up the possibility for manipulation of quantum states. While the limiting cases of ultrafast and continuous-wave excitation have been…
High intensity THz lasers allow for the coherent excitation of individual phonon modes. The ultrafast control of emergent magnetism by means of phonons opens up new tuning mechanisms for functional materials. While theoretically predicted…
Dielectric tensor and lattice dynamics of alpha-PbO2-type TiO2 have been investigated using the density functional perturbation theory, with a focus on responses of the vibrational frequencies to pressure. The calculated Raman spectra under…
We bring forth a consistent theory for the electron-mediated vibrational intermode coupling that clarifies the microscopic mechanism behind the vibrational relaxation of adsorbates on metal surfaces. Our analysis points out the inability of…
We report a theoretical investigation of the ultrafast dynamics of electrons and phonons in strained monolayer WS$_2$ following photoexcitation. We show that strain substantially modifies the phase space for electron-phonon scattering,…
The direct, ultrafast excitation of polar phonons with electromagnetic radiation is a potent strategy for controlling the properties of a wide range of materials, particularly in the context of influencing their magnetic behavior. Here, we…
Multifunctional properties in quantum systems require the interaction between different degrees of freedom. As such, spin-phonon coupling emerges as an ideal mechanism to tune multiferroicity, magnetism, and magnetoelectric response. In…
Manipulating spin in antiferromagnetic (AFM) materials has great potential in AFM opto-spintronics. Laser pulses can induce a transient ferromagnetic (FM) state in AFM metallic systems, but have never been proven in two-dimensional (2D) AFM…
Magnetic layered materials have emerged recently as promising systems to introduce magnetism in structures based on two-dimensional (2D) materials and to investigate exotic magnetic ground states in the 2D limit. In this work, we apply high…
To coherently enhance inherent weak magnetic interactions in rare-earth orthoferrite SmFeO$_3$ as a functional material for spintronic applications, we simulate the dissipative spin dynamics that are linearly and quadratically coupled to…
We report first principles density functional perturbation theory calculations and inelastic neutron scattering measurements of the phonon density of states, dispersion relations and electromechanical response of PbTiO3, BaTiO3 and SrTiO3.…
Engineering of phonons, i.e., collective lattice vibrations in crystals, is essential for manipulating physical properties of materials such as thermal transport, electron-phonon interaction, confinement of lattice vibration, and optical…
The second and third order nonlinear susceptibilities of the ferroelectric oxides LiNbO$_3$, LiTaO$_3$, and KNbO$_3$ are calculated from first principles. Two distinct methodologies are compared, one approach is based on a perturbative…
The novel ferroelectric-like structural transition observed in metallic LiOsO$_3$ [Y. Shi et al., Nat. Mater. 12, 1024 (2013)], has invoked many theoretical and experimental interests. In this work, we have performed polarized and…