scholarly journals Determining EMIC Wave Vector Properties Through Multi‐Point Measurements: The Wave Curl Analysis

2021 ◽  
Vol 126 (4) ◽  
Author(s):  
S. K. Vines ◽  
B. J. Anderson ◽  
R. C. Allen ◽  
R. E. Denton ◽  
M. J. Engebretson ◽  
...  
Keyword(s):  
Wave Vector ◽  
Emic Wave

Effects of Higher-Order Laue Zone reflections on structure images

1993 ◽  
Vol 51 ◽  
pp. 450-451
Author(s):  
H. S. Kim ◽  
S. S. Sheinin
Keyword(s):  
Wave Vector ◽  
Theoretical Calculations ◽  
Reciprocal Lattice ◽  
Image Plane ◽  
Bloch Wave ◽  
Dynamical Theory ◽  
Higher Order ◽  
Lattice Image ◽  
Lattice Vector ◽  
Image Position

The importance of image simulation in interpreting experimental lattice images is well established. Normally, in carrying out the required theoretical calculations, only zero order Laue zone reflections are taken into account. In this paper we assess the conditions for which this procedure is valid and indicate circumstances in which higher order Laue zone reflections may be important. Our work is based on an analysis of the requirements for obtaining structure images i.e. images directly related to the projected potential. In the considerations to follow, the Bloch wave formulation of the dynamical theory has been used.The intensity in a lattice image can be obtained from the total wave function at the image plane is given by: where ϕg(z) is the diffracted beam amplitide given by In these equations,the z direction is perpendicular to the entrance surface, g is a reciprocal lattice vector, the Cg(i) are Fourier coefficients in the expression for a Bloch wave, b(i), X(i) is the Bloch wave excitation coefficient, ϒ(i)=k(i)-K, k(i) is a Bloch wave vector, K is the electron wave vector after correction for the mean inner potential of the crystal, T(q) and D(q) are the transfer function and damping function respectively, q is a scattering vector and the summation is over i=l,N where N is the number of beams taken into account.

Wave-Vector-Varying Pancharatnam-Berry Phase Photonic Spin Hall Effect

2021 ◽  
Vol 126 (8) ◽  
Author(s):  
Wenguo Zhu ◽  
Huadan Zheng ◽  
Yongchun Zhong ◽  
Jianhui Yu ◽  
Zhe Chen
Keyword(s):  
Hall Effect ◽  
Wave Vector ◽  
Berry Phase ◽  
Spin Hall Effect

scholarly journals Mechanisms of electron-phonon coupling unraveled in momentum and time: The case of soft phonons in TiSe2

2021 ◽  
Vol 7 (20) ◽  
pp. eabf2810
Author(s):  
Martin R. Otto ◽  
Jan-Hendrik Pöhls ◽  
Laurent P. René de Cotret ◽  
Mark J. Stern ◽  
Mark Sutton ◽  
...  
Keyword(s):  
Wave Vector ◽  
Density Wave ◽  
Phonon Coupling ◽  
Many Body ◽  
Soft Zone ◽  
Electron Phonon Coupling ◽  
Underlying Mechanisms ◽  
The Many ◽  
Coupling Phenomena ◽  
Electron Pocket

The complex coupling between charge carriers and phonons is responsible for diverse phenomena in condensed matter. We apply ultrafast electron diffuse scattering to unravel electron-phonon coupling phenomena in 1T-TiSe2 in both momentum and time. We are able to distinguish effects due to the real part of the many-body bare electronic susceptibility, R[χ0(q)], from those due to the electron-phonon coupling vertex, gq, by following the response of semimetallic (normal-phase) 1T-TiSe2 to the selective photo-doping of carriers into the electron pocket at the Fermi level. Quasi-impulsive and wave vector–specific renormalization of soft zone-boundary phonon frequencies (stiffening) is observed, followed by wave vector–independent electron-phonon equilibration. These results unravel the underlying mechanisms driving the phonon softening that is associated with the charge density wave transition at lower temperatures.

Nematicons routing through two types of disclination lines in chiral nematic liquid crystals

2014 ◽  
Vol 23 (04) ◽  
pp. 1450042 ◽  
Author(s):  
Michał Kwaśny ◽  
Urszula A. Laudyn ◽  
Katarzyna A. Rutkowska ◽  
Mirosław A. Karpierz
Keyword(s):  
Liquid Crystals ◽  
Wave Vector ◽  
Nematic Liquid Crystals ◽  
Input Beam ◽  
Oriented Sample ◽  
Beam Position ◽  
Chiral Nematic ◽  
Different Types ◽  
Optimal Beam ◽  
Beam Parameters

In this work, we study nematicons propagation at the disclination lines in a wedge-shaped planarly oriented sample. Using optimal beam parameters for light self-trapping and varying the input beam position and direction of the wave vector k with respect to the z-axis, we gain insight in the nematicons propagation in the highly disturbed area around two different types of disclination lines in chiral nematic.

scholarly journals Statistical distribution of EMIC wave spectra: Observations from Van Allen Probes

2016 ◽  
Vol 43 (24) ◽  
pp. 12,348-12,355 ◽  
Author(s):  
X.-J. Zhang ◽  
W. Li ◽  
R. M. Thorne ◽  
V. Angelopoulos ◽  
J. Bortnik ◽  
...  
Keyword(s):  
Statistical Distribution ◽  
Wave Spectra ◽  
Emic Wave ◽  
Van Allen Probes

Wave-vector space picture for radiationless focusing and beaming

2009 ◽  
Vol 34 (19) ◽  
pp. 2967 ◽  
Author(s):  
Varat Intaraprasonk ◽  
Shanhui Fan
Keyword(s):  
Vector Space ◽  
Wave Vector

Dynamic Stability of Ni FCC Crystal under Isotropic Tension

2013 ◽  
Vol 592-593 ◽  
pp. 47-50
Author(s):  
Petr Řehák ◽  
Miroslav Černý
Keyword(s):  
Dynamic Stability ◽  
Wave Vector ◽  
First Principles ◽  
Lattice Dynamics ◽  
Harmonic Approximation ◽  
Tensile Loading ◽  
The Other ◽  
Other Hand ◽  
Critical Strains

Lattice dynamics and stability of fcc crystal of Ni under isotropic (hydrostatic) tensile loading are studied from first principles using supercell method and a harmonic approximation. According to the results, strength of the crystal is determined by occurrence of an instability related to soft phonons with finite wave vector. On the other hand, the critical strains and stresses associated with such instabilities are only slightly lower than those related to the volumetric instability.

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