相关论文: Local structure and its implications for the relax…
We study the energetic stability and the local electronic structure of the general twisted trilayer graphene (TTG) with the top and bottom layers rotated with respect to the middle layer respectively by $\theta$ and $\theta'$. Approximate…
Recently, the prospects for amorphous phases of graphene (a-G) have been explored computationally. Initial models were flat, and contained odd-member rings, while maintaining three-fold coordination and sp2 bonding. Upon relaxation,…
We study dynamics and relaxation of elementary excitations (magnons) in the spin nematic (quadrupole ordered) phase of S=1 magnets. We develop a general phenomenological theory of spin dynamics and relaxation for spin-1 systems. Results of…
We present an ab initio study on the structural and electronic distortions of modified graphene by creation of vacancies, inclusion of boron atoms, and the coexistence of both, by means of thermodynamics and band structure calculations. In…
In this paper, we investigate the electronic band structure, lattice dynamics and electron-phonon interaction in $\delta$-NbN, $\varepsilon$-NbN and WC-NbN by performing systematic ab initio calculations based on DFT-GGA. The calculated…
Motivated by the recent observations of various exotic quantum states in the equilateral triangular-lattice phosphates Na$_2$BaCo(PO$_4$)$_2$ with $J\rm_{eff}$ = 1/2 and Na$_2$BaNi(PO$_4$)$_2$ with $S$ = 1, the magnetic properties of…
Dielectric spectroscopy of a twist bend nematic phase of an achiral bent core liquid crystalline compound under DC bias is used to investigate its response to electric field. Two collective relaxation processes are revealed, these are…
The ferroelectric to paraelectric phase transition of multiferroic CaMnTi$_2$O$_6$ has been investigated at high pressures and ambient temperature by second harmonic generation (SHG), Raman spectroscopy, and powder and single-crystal x-ray…
We report on far- and mid-infrared reflectivity of NdMnO3 from 4 K to 300K. Two main features are distinguished in the infrared spectra: active phonons in agreement with the expected for orthorhombic D2h 16-Pbnm (Z=4) space group remaining…
We investigate transient nonlinear localization, namely the self-excitation of energy bursts in an atomic lattice at finite temperature. As a basic model we consider the diatomic Lennard-Jones chain. Numerical simulations suggest that the…
High purity niobium (Nb), subjected to the processing methods used in the fabrication of superconducting RF cavities, displays micron-sized surface patches containing excess carbon. High-resolution transmission electron microscopy and…
Broadband dielectric spectroscopy was used to study the molecular orientational dynamics of the glass-forming, thioether-linked cyanobiphenyl liquid crystal dimers. As was expected theoretically, two different relaxation processes that…
We present detailed first-principles calculations for the normal state electronic properties of the high T$_C$ superconductor Bi$_2$Sr$_2$CaCu$_2$O$_8$, by means of the linearized augmented plane wave (LAPW) method within the framework of…
We present a comprehensive analysis of the magnetic excitations and electronic properties of fully quantum double-exchange ferromagnets, i.e., systems where ferromagnetic ordering emerges from the competition between spin, charge, and…
First-principles calculations have been conducted to study the structural, vibrational and dielectric properties of {\beta}-Si3N4. Calculations of the zone-center optical-mode frequencies (including LO-TO splittings), Born effective charge…
Motivated by a recent experiment [L.Chomaz et al., Nature Physics 14, 442 (2018)], we perform numerical simulations of a dipolar Bose-Einstein Condensate (BEC) in a tubular confinement at T=0 within Density Functional Theory, where the…
We report on the geometrically frustrated two-dimensional triangular-lattice magnets $A_2$La$_2$NiW$_2$O$_{12}$ ($A$ = Sr, Ba) studied mostly by means of neutron powder diffraction (NPD) and muon-spin rotation and relaxation ($\mu$SR)…
Combining our comprehensive investigations of polarization evolution, soft-mode by Raman scattering and microstructure by TEM, and the results reported in the literatures, we show that prototypical relaxor Pb(Mg1/3Nb2/3)O3 (PMN) is…
Recent experiments on a $\2d$ Fermi gas find an undamped breathing mode at twice the trap frequency over a wide range of parameters. To understand this seemingly scale-invariant behavior in a system with a scale, we derive two exact results…
We study a weakly disordered 2D electron gas with two bands and a spectral node within the weak-localization approach and compare its results with those of Gaussian fluctuations around the self-consistent Born approximation. The appearance…