相关论文: Phonon Kinetics at the Solid to Liquid Phase Trans…
The analysis of phonon anomalies provides valuable information about the cooperative dynamics of lattice, spin and charge degrees of freedom. Significant is the anomalous temperature dependence of the external modes observed in…
A first-principles-based method for computing phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed. The method takes fluctuations of force constants (FCs) due to magnetic excitations as well as due…
The advent of pump-probe spectroscopy techniques paved the way to the exploration of the ultrafast dynamics of electrons and phonons in crystalline solids. Following photo-absorption of a pump pulse and the initial electronic…
Phononic engineering at gigahertz (GHz) frequencies form the foundation of microwave acoustic filters, acousto-optic modulators, and quantum transducers. Terahertz (THz) phononic engineering could lead to acoustic filters and modulators at…
Many complex crystals show a flattening or even increasing lattice thermal conductivity at high temperatures, which deviates from the traditional 1/T decay trend given by conventional phonon theory. In this work, we predict the thermal…
We examine the ultrafast optical response of the crystalline and amorphous phases of the phase change material Ge$_2$Sb$_2$Te$_5$ below the phase transformation threshold. Simultaneous measurement of the transmissivity and reflectivity of…
We combine femtosecond electron diffuse scattering experiments and first-principles calculations of the coupled electron-phonon dynamics to provide a detailed momentum-resolved picture of the ultrafast lattice thermalization in a thin film…
Time-domain THz transmission experiment was performed on a $\rm SrBi_2Ta_2O_9$ film deposited on sapphire substrate. Temperatures between 300 and 923 K were investigated and complex permittivity spectra of the film were determined. The…
We use ultrafast optical spectroscopy to investigate the electronic and lattice dynamics of the charge-density wave (CDW) material 1$T$-TiSe$_2$ across various temperatures and pump fluences. We reveal a close relationship between the…
We investigate the ultrafast optical response of PbTe to an intense single-cycle terahertz pulse, resonant with the soft transverse optical (TO) phonon mode of the crystal. We detect multifrequency oscillations of the reflectance…
The spontaneous condensation of excitons in the excitonic insulating phase has been reported in Ta$_2$NiSe$_5$ below 325 K. In this context, we present the temperature-dependent optical pump optical probe spectroscopy of Ta$_2$NiSe$_5$,…
Terahertz (THz) transmission spectra have been measured as function of temperature and magnetic field on single crystals of Cu3Bi(SeO3)2O2Br. In the time-domain THz spectra without magnetic field, two resonance absorptions are observed…
Magnetic order parameters in altermagnets can couple to quantized lattice vibration via both piezomagnetic and magnetoelastic effects, leading to the renormalization of phonon dispersion. Here, we demonstrate photo-induced dynamic frequency…
We analyze the heat power $P$ between electrons and phonons in thin metallic films deposited on free-standing dielectric membranes in a temperature range in which the phonon gas has a quasi two-dimensional distribution. The quantization of…
Searching multiple types of terahertz (THz) irradiation source is crucial for the THz technology. Here, by utilizing a two-dimensional (2D) ferromagnetic Cr2Ge2Te6 crystal, we firstly demonstrate a magneto-tunable monochromatic THz…
Vibrational dynamics governs the fundamental properties of molecular crystals, shaping their thermodynamics, mechanics, spectroscopy, and transport phenomena. However desirable, the first-principles calculation of solid-state vibrations,…
The plasma oscillations in high-mobility field-effect transistors (HEMTs) have emerged as a key physical mechanism for manipulating electromagnetic radiation in the sub-terahertz (sub-THz) and THz frequency ranges. These collective electron…
Tailored light excitation and nonlinear control of lattice vibrations have emerged as powerful strategies to manipulate the properties of quantum materials out of equilibrium. Generalizing the use of coherent phonon-phonon interactions to…
We report the first study on the thermal behaviour of the stiffness of individual carbon nanotubes, which is achieved by measuring the resonance frequency of their fundamental mechanical bending modes. We observe a reduction of the Young's…
The temperature and strain dependences of the optical conductivity spectrum of hexagonal manganese telluride (MnTe) were measured, revealing absorption in the terahertz (THz) region from spin-split bands to acceptor levels. The temperature…