Bulk Crystal Growth of Hg1−xCdxTe for Avalanche Photodiode Applications

1986 ◽  
Vol 90 ◽  
Author(s):  
T. Nguyen Duy ◽  
A. Durand ◽  
J. L. Lyot
Keyword(s):  
Composition Range ◽  
Resonance Effect ◽  
Avalanche Photodiode ◽  
Bandgap Energy ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
Bulk Crystal Growth ◽  
Spin Orbit Splitting ◽  
Rich Alloy

ABSTRACTHigh gap Hg1−xCdxTe (MCT) crystal is grown by a solvent method using a travelling heater zone. The use of the solvent zone permits a low temperature and low mercury pressure growth of MCT in a large composition range. In the Cadmium rich alloy range the MCT material exhibits a large spin orbit coupling leading to a resonance at Eg = ΔO. Due to this particular resonance effect the ionization coefficient of hole is higher than that of the electron, resulting in a low exess noise factor in the avalanche photodiodes whose bandgap energy is close to the spin orbit splitting ΔO.

The calculation of spin-orbit splitting and g tensors for small molecules and radicals

1973 ◽  
Vol 332 (1590) ◽  
pp. 365-384 ◽  
Keyword(s):  
Order Effects ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
First Order ◽  
Spin Orbit Splitting ◽  
Approximate Form ◽  
Firm Basis ◽  
Semi Empirical ◽  
Good Agreement

The spin-orbit coupling terms in the molecular electronic Hamiltonian have important, spectroscopically observable, effects. In states possessing an orbital degeneracy (e.g. II states of diatomic molecules) they produce a first-order splitting of the various multiplet levels; and in states which are degenerate in spin only the y give second-order effects embodied in a n effective g tensor. Owing to the complexity of the spin-orbit operators, such effects are usually discussed using simple approximate form s and semi-empirical wave-functions. In this paper, the complete operators are employed in ab initio calculations of (i) the spin-orb it splitting of the 2 II ground states of NO and CH, and (ii) the g tensors of CN and NO 2 . The results are in good agreement with experiment. Detailed analysis of the calculations indicates a firm basis for semi-empirical procedures which could easily be applied to larger molecules. The evaluation of new integrals, involving the spin-orbit operators, is discussed in an appendix.

Spin–orbit splitting in graphene, silicene and germanene: Dependence on buckling

2018 ◽  
Vol 32 (05) ◽  
pp. 1850055 ◽  
Author(s):  
Ranber Singh
Keyword(s):  
Valence Band ◽  
Valence Band Maximum ◽  
Honeycomb Structure ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
Band Maximum ◽  
Honeycomb Structures ◽  
Spin Orbit Splitting

The spin–orbit splitting (E[Formula: see text]) of valence band maximum at the [Formula: see text] point is significantly smaller in 2D planner honeycomb structures of graphene, silicene, germanene and BN than that in the corresponding 3D bulk counterparts. For 2D planner honeycomb structure of SiC, it is almost same as that for 3D bulk cubic SiC. The bandgap which opens at the K and K[Formula: see text] points due to spin–orbit coupling (SOC) is very small in flat honeycomb structures of graphene and silicene, while in germanene it is about 2 meV. The buckling in these structures of graphene, silicene and germanene increases the bandgap opened at the K and K[Formula: see text] points due to SOC quadratically, while the E[Formula: see text] of valence band maximum at the [Formula: see text] point decreases quadratically with an increase in the magnitude of buckling.

Spin–orbit splitting in 2Δ states of diatomic molecules

1969 ◽  
Vol 47 (23) ◽  
pp. 2727-2730 ◽  
Author(s):  
H. Lefebvre-Brion ◽  
N. Bessis
Keyword(s):  
Diatomic Molecules ◽  
Orbit Interaction ◽  
Second Order ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Good Agreement

The origin of the splitting of the 2Δ states arising from the σπ2 configuration is studied. For light diatomic molecules, the splitting is shown to arise from the spin–other–orbit interaction which gives a small negative value for the spin–orbit coupling constant A. Non-empirical calculations of A for the 2Δ states of the CH, NH+, and NO molecules are in good agreement with experiment. In heavier molecules, the spin–other–orbit interaction becomes negligible and the second-order spin–orbit effect is dominant.

scholarly journals The bandgap energy of the dilute bismuth GaBi x Sb1−x alloy depending on temperature

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Chuan-Zhen Zhao ◽  
Xue-Lian Qi
Keyword(s):  
Temperature Dependence ◽  
Valence Band ◽  
Bandgap Energy ◽  
Spin Orbit ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Increasing Trend ◽  
Reduced Temperature

Abstract The bandgap energy of the dilute bismuth GaBi x Sb1−x alloy vs. temperature is investigated in this study. Its reduced temperature-sensitiveness is because of the localized character of the valence band states (VBS). In order to describe the reduced temperature-sensitiveness of the bandgap energy, a new term including localized energy is added to Varshni's equation. It is found that the localized energy exhibits an increasing trend as the bismuth fraction increases, which indicates that the localized character of the VBS becomes strong with the increasing bismuth fraction. It is also found that the influence of the bismuth fraction on the temperature dependence of the bandgap energy of GaBi x Sb1−x is smaller than that of GaBi x As1−x . In addition, the element indium is undoubtedly a good candidate to lessen the bismuth fraction to realize that the spin-orbit-splitting (SOP) energy surpasses the bandgap energy in GaBi x Sb1−x .

The sign of the spin-orbit coupling constant in (t 2 ) 5 2 T 2 states of AX + 4 ions

1988 ◽  
Vol 324 (1578) ◽  
pp. 293-294
Keyword(s):  
Open Shell ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Coupling Constant ◽  
Orbit Splitting ◽  
Atomic Spin ◽  
Spin Orbit Splitting

The spin-orbit splitting in orbitally degenerate systems with one open shell usually conforms to Hund’s third rule: that is, the splitting is regular for a less than half-filled shell, and inverted for a more than half-filled shell. The C 2 T 2 states of CF+4 and SiF+4 reported by Mason & Tuckett violate this expectation. We show below how this may occur in AX+4 ions where the dominant atomic spin-orbit coupling arises from motion around the X atoms.

Reversible engineering of spin-orbit splitting in monolayer MoS2 via laser irradiation under controlled gas atmospheres

Nanoscale ◽  
2021 ◽  
Author(s):  
Xilong Liang ◽  
Chengbing Qin ◽  
Yan Gao ◽  
Shuangping Han ◽  
Guofeng Zhang ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Transition Metal Dichalcogenides ◽  
Inversion Symmetry ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Monolayer Mos2 ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Metal Dichalcogenides ◽  
Strong Spin

Monolayer transition metal dichalcogenides, manifesting strong spin-orbit coupling combined with broken inversion symmetry, lead to a coupling of spin and valley degrees of freedom. These unique features make them highly...

Vibrational dependence of the rotational, spin-orbit splitting, and lambda-doubling parameters in the C″5Πui state of N2 This article is part of a Special Issue on Spectroscopy at the University of New Brunswick in honour of Colan Linton and Ron Lees.

2009 ◽  
Vol 87 (5) ◽  
pp. 601-606 ◽  
Author(s):  
O. Pirali ◽  
D. W. Tokaryk ◽  
M. Vervloet
Keyword(s):  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Special Issue ◽  
Infrared Band ◽  
Orbit Splitting ◽  
Supersonic Expansion ◽  
Spin Orbit Splitting ◽  
Vibrational Levels ◽  
Set Up ◽  
The University

We have recorded the high-resolution emission spectrum of the Herman infrared band (C″5Πui–A′5Σ g+ ) system of N2 in the 8000–15000 cm–1 range from an experimental set-up coupling a corona discharge with a supersonic expansion. The analysis of four new bands has permitted us to determine spectroscopic parameters of the v′ = 0 and v′ = 1 vibrational levels of the C″5Πui state and to study the vibrational dependence of the molecular parameters over the range v′ = 0 to v′ = 4. In particular, the values of the spin-orbit coupling and the Λ–doubling parameters are discussed.

Energy levels in rare-earth ions

1957 ◽  
Vol 240 (1223) ◽  
pp. 509-523 ◽  
Keyword(s):  
Rare Earth ◽  
Energy Levels ◽  
Rare Earth Ions ◽  
Tensor Operator ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Rare Earth Ion ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
The One

The tensor-operator and group-theoretical methods of Racah are used to examine the following contributions to the Hamiltonian of a rare-earth ion: ( a ) the Coulomb interaction between the electrons, ( b ) the spin-orbit coupling of the electrons, and ( c ) the term arising from the influence of an external electrostatic field such as occurs when the rare-earth ion is situated in a crystal lattice. With regard to ( a ), the positions of all the terms of the configurations f 2 , f 3 and f 4 , as well as all the terms of other configurations f n whose multiplicities are the highest or the highest but one, are tabulated on the basis of a hydrogenic 4 f wave function. The theory of ( b ) is developed, and the parameter λ defining the spin-orbit splitting of a term is given for all terms whose energies have been found, ( c ) is treated by similar techniques and the theory is related to the one at present in use. All the general methods are illustrated by examples.

Spin -Orbit Coupling in the O-2 Anion

1995 ◽  
Vol 50 (11) ◽  
pp. 1041-1044 ◽  
Author(s):  
J. Schiedt ◽  
R. Weinkauf
Keyword(s):  
High Resolution ◽  
Electron Energy ◽  
Ground State ◽  
Photoelectron Spectroscopy ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Energy Analyzer ◽  
Orbit Splitting ◽  
Spin Orbit Splitting ◽  
Good Agreement

Abstract We could resolve the spin-orbit splitting of 160 ± 4 cm-1 in the 2II ground state of O2- anions by high resolution photodetachment photoelectron spectroscopy. The observed splitting is in good agreement with the theoretically derived value. Our directly measured electron affinity of O 2 is 450 ± 2 meV and deviates within experiment errors from previous values. kHz repetition rate was applied to avoid space charge and improve electron energy resolution in a time-of-flight electron energy analyzer.

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