Breaking inversion symmetry induces excitonic peak in optical absorption of topological semimetal

2017 ◽  
Vol 100 ◽  
pp. 161-169 ◽  
Author(s):  
Mehrdad Dadsetani ◽  
Ali Ebrahimian
Keyword(s):  
Optical Absorption ◽  
Inversion Symmetry ◽  
Excitonic Peak ◽  
Topological Semimetal

STRUCTURES AND OPTICAL PROPERTIES OF HYDRAZONES DERIVED FROM BIOLOGICAL POLYENES

2001 ◽  
Vol 15 (28n30) ◽  
pp. 3893-3896 ◽  
Author(s):  
TAKAYASU NAKASHIMA ◽  
TAKASHI YAMADA ◽  
HIDEKI HASHIMOTO ◽  
TAKAYOSHI KOBAYASHI
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Potential Energy Surfaces ◽  
Molecular Structures ◽  
Optical Absorption Spectroscopy ◽  
Inversion Symmetry ◽  
Polyene Chain ◽  
X Ray Crystallography ◽  
The One ◽  
Chain Lengths

A set of hydrazone molecules was derived from a series of biological polyenes that have different polyene chain-lengths with common substituent group of 2,4-dinitrophenylhydrazine. Their structures were determined by high-resolution NMR spectroscopy as well as X-ray crystallography, and their optical properties were investigated by room and low temperature optical absorption spectroscopy. Among the derivatives so far synthesized, the one that has the shortest polyene chain (C13-DNPH) afforded single crystals without inversion symmetry, hence applicable for the second-order nonlinear optical devices. Molecular structures in the crystals were closely inspected in order to explain the cause to violate the inversion symmetry. Hydrazones derived in this study gave rise to two transition moments along the molecular axis. Comparison of the optical absorption spectra among the derivatives showed a unique phenomenon that could be attributed to the crossover of the excited state potential energy surfaces along the elongation of the polyene chain-lengths.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

Optical absorption in PdH

1982 ◽  
Vol 43 (2) ◽  
pp. 323-328 ◽  
Author(s):  
M.A. Khan ◽  
R. Riedinger
Keyword(s):  
Optical Absorption

IRREVERSIBLE PHOTOINDUCED CHANGE IN THE OPTICAL ABSORPTION OF YIG(Si) ON IRRADIATION

1971 ◽  
Vol 32 (C1) ◽  
pp. C1-794-C1-795
Author(s):  
J. F. DILLON ◽  
Jr ◽  
E. M. GYORGY ◽  
J. P. REMEIKA
Keyword(s):  
Optical Absorption ◽  
Photoinduced Change

OPTICAL ABSORPTION OF SOLID NEON AND ARGON IN THE SOFT X-RAY REGION

1971 ◽  
Vol 32 (C4) ◽  
pp. C4-236-C4-240 ◽  
Author(s):  
R. HAENSEL ◽  
G. KEITEL ◽  
N. KOSUCH ◽  
U. NIELSEN ◽  
P. SCHREIBER
Keyword(s):  
Optical Absorption ◽  
X Ray

OPTICAL ABSORPTION OF Co2+ IN ZnO

1976 ◽  
Vol 37 (C7) ◽  
pp. C7-203-C7-203
Author(s):  
P. KOIDL
Keyword(s):  
Optical Absorption
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