相关论文: Nonlinear phononics in Bi$_2$Te$_3$ nanoscale thin…

Anharmonic lattice vibrations play a key role in many physical phenomena. They govern the heat conductivity of solids, strongly affect the phonon spectra, play a prominent role in soft mode phase transitions, allow ultrafast engineering of…

A density functional theory (DFT) framework is presented that links functional derivatives of free-energy functionals to non-linear static density response functions in quantum many-body systems. Within this framework, explicit expressions…

First-principles calculations are used in order to investigate phonon anomalies in non-magnetic and magnetic Heusler alloys. Phonon dispersions for several systems in their cubic L2$\mathrm{_1}$ structure were obtained along the [110]…

We tailor the shape and phase of the pump pulse spectrum in order to study the coherent lattice dynamics in tellurium. Employing the coherent control via splitting the pump pulse into a two-pulse sequence, we show that the oscillations due…

The high breakdown current densities and resilience to scaling of the metallic transition metal trichalcogenides TaSe3 and ZrTe3 make them of interest for possible interconnect applications, and it motivates this study of their thermal…

In view of their immensely intriguing properties, two dimensional materials are being intensely researched in search of novel phenomena and diverse application interests, however, studies on the realization of nanocomposites in the…

Direct detection of phonons is important for the investigation of information interconversion between the resonantly coupled magnons and phonons. Here we report resonant coupling of magnons and phonons, which can be directly visualized by…

The emergence of phonon frequency combs exemplifies a rare and intriguing phenomenon in quantum solids. Materials with distinctive phonon band structures are especially promising for hosting such states, as their vibrational dispersion…

Small polaron formation in transition metal oxides, like the prototypical material rutile TiO$_2$, remains a puzzle and a challenge to simple theoretical treatment. In our combined experimental and theoretical study, we examine this problem…

Density functional theory and density functional perturbation theory are used to investigate the electronic and vibrational properties of TiS$_2$. Within the local density approximation the material is a semi-metal both in the bulk and in…

Cuprate superconductors host a multitude of low-energy optical phonons. Using time- and angle-resolved photoemission spectroscopy, we study coherent phonons in Bi$_{2}$Sr$_{2}$Ca$_{0.92}$Y$_{0.08}$Cu$_{2}$O$_{8+\delta}$. Sub-meV modulations…

1$T$-TaSe$_{2}$ is host to coexisting strongly-correlated phases including charge density waves (CDWs) and an unusual Mott transition at low temperature. Here, we investigate coherent phonon oscillations in 1$T$-TaSe$_{2}$ using a…

Direct manipulation of the atomic lattice using intense long-wavelength laser pulses has become a viable approach to create new states of matter in complex materials. Conventionally, a high frequency vibrational mode is driven resonantly by…

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$_5$,…

We investigate the temperature dependence of photon coherence properties through two photon interference (TPI) measurements from a single QD under resonant excitation. We show that the loss of indistinguishability is only related to the…

Density Functional Resonance Theory (DFRT) is a complex-scaled version of ground-state Density Functional Theory (DFT) that allows one to calculate the resonance energies and lifetimes of metastable anions. In this formalism, the exact…

We introduce and model a three-dimensional (3D) atomic-scale phononic metamaterial producing two-path phonon interference antiresonances to control the heat flux spectrum. We show that a crystal plane partially embedded with defect-atom…

When mid-infrared light interacts with nanoscale polar dielectric structures optical phonon propagation cannot be ignored, leading to a rich nonlocal phenomenology which we have only recently started to uncover. In properly crafted…

Phonon drag may be harnessed for thermoelectric generators and devices. Here, we demonstrate the geometric control of the phonon-drag contribution to the thermopower. In nanometer-thin electrically conducting $\beta$-Ga$_2$O$_3$ films…

While the vibrational thermodynamics of materials with small anharmonicity at low temperatures has been understood well based on the harmonic phonons approximation; at high temperatures, this understanding must accommodate how phonons…