Quantum Energy Gap in the S=1 Heisenberg Antiferromagnet NENP: Experimental Data and Haldane Conjecture

1987 ◽  
pp. 449-452
Author(s):  
J. P. Renard ◽  
M. Verdaguer ◽  
L. P. Regnault ◽  
W. A. C. Erkelens ◽  
J. Rossat-Mignod ◽  
...  
Keyword(s):  
Experimental Data ◽  
Energy Gap ◽  
Heisenberg Antiferromagnet ◽  
Quantum Energy

Presumption for a Quantum Energy Gap in the Quasi-One-Dimensional S = 1 Heisenberg Antiferromagnet Ni(C 2 H 8 N 2 ) 2 NO 2 (ClO 4 )

1987 ◽  
Vol 3 (8) ◽  
pp. 945-952 ◽  
Author(s):  
J. P Renard ◽  
M Verdaguer ◽  
L. P Regnault ◽  
W. A. C Erkelens ◽  
J Rossat-Mignod ◽  
...  
Keyword(s):  
Energy Gap ◽  
Heisenberg Antiferromagnet ◽  
Quantum Energy ◽  
One Dimensional

scholarly journals Direct observation of the quantum energy gap in S = ½ tetragonal cuprate antiferromagnets

2001 ◽  
Vol 54 (4) ◽  
pp. 508-514 ◽  
Author(s):  
K Katsumata ◽  
M Hagiwara ◽  
Z Honda ◽  
J Satooka ◽  
A Aharony ◽  
...  
Keyword(s):  
Direct Observation ◽  
Energy Gap ◽  
Quantum Energy

Electron transport and conduction band structure of GaSb

1981 ◽  
Vol 59 (12) ◽  
pp. 1844-1850 ◽  
Author(s):  
Hyung Jae Lee ◽  
John C. Woolley
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
Electrical Conductivity ◽  
Conduction Band ◽  
Room Temperature ◽  
Energy Gap ◽  
Band Model ◽  
Scattering Coefficients ◽  
Wide Range ◽  
Different Temperatures

Calculations have been made using the Fletcher and Butcher method in a three conduction band model to fit a wide range of experimental transport data for n-type samples of GaSb: viz. Hall coefficient and electrical conductivity as a function of temperature and as a function of pressure at room temperature, magnetoresistance as a function of magnetic field at different temperatures, and Nernst–Ettingshausen coefficients as a function of magnetic field. Various energy gap parameters and scattering coefficients have been taken as adjustable and values determined for these which give good fits to all of the experimental data. Values of mobility for each of the Γ, L, and X bands have then been calculated as a function of temperature.

ELECTRONIC, OPTICAL AND MECHANICAL PROPERTIES OF AIIBVI SEMICONDUCTORS

2012 ◽  
Vol 26 (08) ◽  
pp. 1250020 ◽  
Author(s):  
DHEERENDRA SINGH YADAV ◽  
A. S. VERMA
Keyword(s):  
Experimental Data ◽  
Mechanical Properties ◽  
Energy Gap ◽  
Average Energy ◽  
Compound Semiconductors ◽  
Electronic Polarizability ◽  
Zinc Blende ◽  
Energy Gaps ◽  
Optical And Mechanical Properties ◽  
Good Agreement

The modified dielectric theory of solids is applied to investigate electronic, optical and mechanical properties of A II B VI binary semiconductors ( ZnO, ZnS, ZnSe, ZnTe, CdO, CdS, CdSe, CdTe, HgS, HgSe & HgTe ). The values of homopolar gaps (Eh), heteropolar gaps (Ec) and average energy gaps (Eg) were evaluated for these A II B VI groups of binary semiconductors with Zinc-blende (ZB) structure. The derived values of average energy gap (Eg) were found to be in excellent agreement with the values obtained from the Penn model except ZnO . The electronic polarizability was investigated using Chemla's relation and the values were found to be in a very good agreement with the results obtained from the Clausius–Mossotti relation. The crystal ionicity (fi) was evaluated and the obtained values were compared with the values obtained by different researchers. The evaluated values of crystal ionicity were used to calculate the electronic, optical, mechanical properties such as bulk modulus (B in GPa) cohesive energy or total energy (U in Ryd. electron) and microhardness (H in GPa) of these compound semiconductors. A good agreement has been found between calculated and experimental data.

Ion Beam Irradiation Effects on Polymers

2003 ◽  
Vol 792 ◽  
Author(s):  
Mircea Chipara
Keyword(s):  
Experimental Data ◽  
Free Radicals ◽  
Energy Gap ◽  
Ion Beam ◽  
Beam Irradiation ◽  
Irradiation Effects ◽  
Ion Beam Irradiation ◽  
Radiation Induced ◽  
Main Effects

ABSTRACTThe main effects of the interaction of accelerated ions with polymeric targets are critically reviewed. The possibility of a relatively reduced heating of polymer during ion beam bombardment is analyzed. Experimental data pointing towards various radiation-induced modifications in polycarbonate (free radicals production, modifications of the energy gap) are discussed.

Calculated specific heat and susceptibility for the quadratic Heisenberg antiferromagnet, compared with experimental data on Cu(C5H5NO)6(BF4)2

Physica B+C ◽  
1977 ◽  
Vol 86-88 ◽  
pp. 693-695 ◽  
Author(s):  
R. Navarro ◽  
H.A. Algra ◽  
L.J. De Jongh ◽  
R.L. Carlin ◽  
C.J. O'Connor
Keyword(s):  
Experimental Data ◽  
Specific Heat ◽  
Heisenberg Antiferromagnet

scholarly journals Novel Empirical Correlation Between the Optical Refractive Index and Energy Bandgap in Semiconductors: Comparative Study

2021 ◽  
Author(s):  
Hosam Mohamed Gomaa ◽  
I.S. Yahia ◽  
H.Y. Zahran
Keyword(s):  
Experimental Data ◽  
Refractive Index ◽  
Comparative Study ◽  
Optical Band Gap ◽  
Energy Gap ◽  
Theoretical Studies ◽  
Oxide Glasses ◽  
High Agreement ◽  
Different Types ◽  
Number Of Publications

Abstract This work is an attempt to review some of the most famous and important studies to correlate the optical-linear refractive index of a substance to its energy band-gap.The refractive index of different types of materials, like semiconductors, insulators, oxides, thin-films, and oxide glasses, has been reported in a large number of publications in attempts to the estimation of how it can be correlated to the optical band-gap. The present work can be considered as a comparative study between the most successful relations in correlating the refractive index to the energy gap. The careful reviewing of the previous studies to correlate the optical refractive index and energy gap led to concluded that Reddy and Ahmmed approximation was selected to develop a new realized form that can give a good fit to the experimental data and, hence, be used directly as an accurate formula in the theoretical studies. The obtained formula correlates the optical refractive index to the energy gap and the oxygen atom's electronegativity. Such relation has been used to calculate the refractive indices for more than 96 materials (elements/compounds) with a high agreement with the experimental data.

REPRODUCIBLE TUNNELING MEASUREMENTS IN CERAMIC Y1Ba2Cu3O7−x SAMPLES WITH DIFFERENT OXYGEN CONTENT

1991 ◽  
Vol 05 (11) ◽  
pp. 1899-1912 ◽  
Author(s):  
R. S. GONNELLI ◽  
G. F. DURIN ◽  
D. ANDREONE ◽  
V. LACQUANITI ◽  
C. APPINO ◽  
...  
Keyword(s):  
Experimental Data ◽  
Oxygen Content ◽  
Proximity Effect ◽  
Energy Gap ◽  
Point Contact ◽  
Tunneling Current ◽  
Sample Surface ◽  
Quasi Particle ◽  
Linear Behaviour ◽  
Particle Current

A large number of tunneling measurements on ceramic monophasic Y 1 Ba 2 Cu 3 O 7−x samples with different oxygen content using the point-contact geometry was performed. After a deconvolution procedure for removing the thermal broadening, experimental data were analyzed by means of a model of the total tunneling current which contains two terms: A background "normal" tunneling current and a quasi-particle tunneling one. The quasi-particle current was expressed in terms of the lifetime broadening model. The dependence of the energy gap Δ and of the lifetime broadening parameter Γ, as determined by the model, on the temperature of the sample is discussed. A linear behaviour in the dependence of the gap on the critical temperature of the sample has been found. The ratio 2Δ/kT c varies between 4.3 and 7.2 depending on the value of T c which can be attributed to the sample surface. The possible presence of proximity effect in our tunneling experiments is also discussed.

Temperature dependence of the energy gap in semiconductors

1984 ◽  
Vol 62 (3) ◽  
pp. 285-287 ◽  
Author(s):  
A. Manoogian ◽  
J. C. Woolley
Keyword(s):  
Experimental Data ◽  
Vibrational Frequency ◽  
Energy Gap ◽  
Order Approximation ◽  
Approximate Equation ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Energy Gaps ◽  
Dilation Effect ◽  
Interaction Term

It is shown that the equation ΔE = αT2/(T + β), which is commonly used to describe the temperature variation of energy gaps in semiconductors, is a second order approximation of the electron–phonon interaction term in the recently proposed equation ΔE = UTs + Vθ[coth (θ/2T) – 1]. The calculation shows that the parameters α and β of the approximate equation can describe the characteristics of semiconductors only if the relation [Formula: see text] holds, with the validity limited by the magnitude of the existing dilation effect. In this case it is found that β = θ/2 where θ is the effective Einstein vibrational frequency, in temperature units, of the phonon spectrum in the material. A comparison of the two equations when fitted to experimental data is presented and discussed.

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