scholarly journals Symmetry Breakdown in Franckeite: Spontaneous Strain, Rippling, and Interlayer Moiré

Nano Letters ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 1141-1147 ◽  
Author(s):  
Riccardo Frisenda ◽  
Gabriel Sanchez-Santolino ◽  
Nikos Papadopoulos ◽  
Joanna Urban ◽  
Michal Baranowski ◽  
...  
Keyword(s):  
Spontaneous Strain ◽  
Symmetry Breakdown

scholarly journals Symmetry Breakdown in Franckeite: Spontaneous Strain, Rippling and Interlayer Moiré

2019 ◽  
Author(s):  
Riccardo Frisenda ◽  
Gabriel Sanchez-Santolino ◽  
Nikos Papadopoulos ◽  
Joanna Urban ◽  
Michal Baranowski ◽  
...  
Keyword(s):  
Optical Properties ◽  
Plane Strain ◽  
Van Der Waals ◽  
Van Der Waals Interaction ◽  
Spatial Modulation ◽  
Two Dimensional ◽  
Spontaneous Strain ◽  
Strain Profile ◽  
Symmetry Breakdown ◽  
Naturally Occurring

<p>Franckeite is a naturally occurring layered mineral with a structure composed of alternating stacks of SnS<sub>2</sub>-like and PbS-like layers. Although this superlattice is composed of a sequence of isotropic two-dimensional layers, it exhibits a spontaneous rippling that makes the material structurally anisotropic. We demonstrate that this rippling comes hand in hand with an inhomogeneous in-plane strain profile and anisotropic electrical, vibrational and optical properties. We argue that this symmetry breakdown results from a spatial modulation of the van der Waals interaction between layers due to the SnS<sub>2</sub>-like and PbS-like lattices incommensurability.</p>

scholarly journals Symmetry Breakdown in Franckeite: Spontaneous Strain, Rippling and Interlayer Moiré

2019 ◽  
Author(s):  
Riccardo Frisenda ◽  
Gabriel Sanchez-Santolino ◽  
Nikos Papadopoulos ◽  
Joanna Urban ◽  
Michal Baranowski ◽  
...  
Keyword(s):  
Optical Properties ◽  
Plane Strain ◽  
Van Der Waals ◽  
Van Der Waals Interaction ◽  
Spatial Modulation ◽  
Two Dimensional ◽  
Spontaneous Strain ◽  
Strain Profile ◽  
Symmetry Breakdown ◽  
Naturally Occurring

<p>Franckeite is a naturally occurring layered mineral with a structure composed of alternating stacks of SnS<sub>2</sub>-like and PbS-like layers. Although this superlattice is composed of a sequence of isotropic two-dimensional layers, it exhibits a spontaneous rippling that makes the material structurally anisotropic. We demonstrate that this rippling comes hand in hand with an inhomogeneous in-plane strain profile and anisotropic electrical, vibrational and optical properties. We argue that this symmetry breakdown results from a spatial modulation of the van der Waals interaction between layers due to the SnS<sub>2</sub>-like and PbS-like lattices incommensurability.</p>

scholarly journals Symmetry Breakdown Related Fracture in 42CrMo4 Steel

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 344
Author(s):  
Jian Feng ◽  
Stefan Barth ◽  
Marc Wettlaufer
Keyword(s):  
Orientation Distribution ◽  
High Symmetry ◽  
Symmetry Breakdown ◽  
Pole Figures ◽  
Crystallographic Symmetry ◽  
42Crmo4 Steel ◽  
Austenite Grains ◽  
Ebsd Technique ◽  
Complete Transformation ◽  
Start Temperature

Austenite grains that underwent the f.c.c. to b.c.c. (or b.c.t.) transformation are typically composed of 24 Kurdjumov–Sachs variants that can be categorized by three axes of Bain transformations; thus, a complete transformation generally displays 3-fold symmetry in (001) pole figures. In the present work, crystallographic symmetry in 42CrMo4 steel austempered below martensite start temperature was investigated with the help of the orientation distribution function (ODF) analysis based on the FEG-SEM/EBSD technique. It is shown that, upon phase transformations, the specimens contained 6-fold symmetry in all (001), (011), and (111) pole figures of an ODF. The ODF analysis, verified by theoretical modeling, showed that under plane-strain conditions cracks prefer to propagate through areas strongly offset by the high symmetry. The origin of high symmetry was investigated, and the mechanism of the symmetry breakdown was explained.

Condensate preserving the symmetry of the Lagrangian. Symmetry breakdown

JETP Letters ◽  
2005 ◽  
Vol 82 (7) ◽  
pp. 394-397
Author(s):  
V. V. Vladimirskii
Keyword(s):  
Symmetry Breakdown

Spontaneous strain of conductive strontium titanate Sr1−xLaxTiO3measured by using X-ray topographic domain contrast

2011 ◽  
Vol 84 (9-10) ◽  
pp. 837-842 ◽  
Author(s):  
T. Ozaki ◽  
K. Kusunose ◽  
H. Yamaguchi ◽  
K. Kajiwara ◽  
Y. Chikaura
Keyword(s):  
Strontium Titanate ◽  
Spontaneous Strain ◽  
X Ray

scholarly journals Symmetry breakdown and coupling constants of leptons

2007 ◽  
Vol 79 (2) ◽  
pp. 195-208 ◽  
Author(s):  
Gil C. Marques ◽  
Dominique Spehler
Keyword(s):  
Coupling Constants ◽  
Electroweak Interactions ◽  
New Approach ◽  
Fundamental Interactions ◽  
Electromagnetic Interactions ◽  
Symmetry Breakdown ◽  
A Value ◽  
Intermediate Bosons ◽  
The One ◽  
The Way

Based on a new approach to symmetries of the fundamental interactions we deal, in this paper, with the electroweak interactions of leptons. We show that the coupling constants, arising in the way leptons are coupled to intermediate bosons, can be understood as parameters associated to the breakdown of SU(2) and parity symmetries. The breakdown of both symmetries is characterized by a new parameter (the asymetry parameter) of the electroweak interactions. This parameter gives a measure of the strength of breakdown of symmetries. We analyse the behaviour of the theory for three values of this parameter. The most relevant value is the one for which only the electromagnetic interactions do not break parity (the maximally allowed left-right asymetric theory). Maximamally allowed parity asymmetry is a requirement that is met for a value of Weinberg's theta-angle that is quite close to the experimental value of this parameter.

scholarly journals Symmetry breakdown of electron emission in extreme ultraviolet photoionization of argon

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
M. Ilchen ◽  
G. Hartmann ◽  
E. V. Gryzlova ◽  
A. Achner ◽  
E. Allaria ◽  
...  
Keyword(s):  
Electron Emission ◽  
Extreme Ultraviolet ◽  
Symmetry Breakdown

scholarly journals Monoclinic–orthorhombic first-order phase transition in K2ZnSi5O12 leucite analogue; transition mechanism and spontaneous strain analysis.

2021 ◽  
pp. 1-20
Author(s):  
Anthony M.T. Bell ◽  
Francis Clegg ◽  
Christopher M.B. Henderson
Keyword(s):  
Phase Transition ◽  
Strain Analysis ◽  
Phase Region ◽  
Martensitic Transition ◽  
Two Phase ◽  
Spontaneous Strain ◽  
First Order ◽  
Transition Mechanism ◽  
First Order Phase Transition ◽  
Increasing Temperature

Abstract Hydrothermally synthesised K2ZnSi5O12 has a polymerised framework structure with the same topology as leucite (KAlSi2O6, tetragonal I41/a), which has two tetrahedrally coordinated Al3+ cations replaced by Zn2+ and Si4+. At 293 K it has a cation-ordered framework P21/c monoclinic structure with lattice parameters a = 13.1773(2) Å, b = 13.6106(2) Å, c = 13.0248(2) Å and β = 91.6981(9)°. This structure is isostructural with K2MgSi5O12, the first cation-ordered leucite analogue characterised. With increasing temperature, the P21/c structure transforms reversibly to cation-ordered framework orthorhombic Pbca. This transition takes place over the temperature range 848−863 K where both phases coexist; there is an ~1.2% increase in unit cell volume between 843 K (P21/c) and 868 K (Pbca), characteristic of a first-order, displacive, ferroelastic phase transition. Spontaneous strain analysis defines the symmetry- and non-symmetry related changes and shows that the mechanism is weakly first order; the two-phase region is consistent with the mechanism being a strain-related martensitic transition.

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