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1.
The influence of uniaxial pressure (0 < P < 2600 kg/cm2) on the intrinsic photoconductivity (PC) spectrum of p-InSb at 93 and 15°K is investigated. At 77°K the carrier concentration and mobility in the specimens were, respectively, (1.4–3.2)·1014 cm–3 and 7000 cm2/V. sec. It is established that the maximum in the PC(Em) spectra under compression is shifted towards higher energies. In the low-compression range Em/P=5·10–6eV·cm2/kg, while Em/P=1·10–6eV·cm2/kg for P > 1000 kg/cm2. It is shown that the shift of the maximum of the intrinsic PC spectra with pressure is due to the growC;th in the forbidden bandwidth (Eg), and the change in parameters characterizing carrier diffusion in the specimen bulk (the diffusion coefficient, lifetime, surface recombination velocity) plays no part. The change in Em/P with pressure is explained by the influence of valence band splitting. The deformation potential constants of the valence band |b|=(1.7±0.3) eV and |d|=(4.4±0.8)eV are calculated on the basis of a comparison between experimentally obtained data and theoretical results.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 159–162, February, 1976. 相似文献
2.
The properties of p-type ZnGeP2 [p0=(5–10)·1010 cm–3, 0=(2–5)·10–7 (·cm)–1], irradiated with H+ ions [E=5 MeV, Tirr=300 K, D=(1·1012–1.7·1016) cm–2] are studied. An increase in the resistivity (to grmax - 5·1011 ·cm) and subsequent reduction in for large currents of H+ ions ( - 9·108 ·cm for D - 1.7·1016 cm–2), is observed in irradiated crystals. The resistivity of irradiated p-type ZnGeP2 is found to be very sensitive to hydrostatic pressure [(4–5)·10–5 bar–1]. The annealing of radiation defects in the temperature interval (20–600) °C is examined.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 91–93, October, 1991. 相似文献
3.
T. Nishida M. Katada N. Osawa R. Sato T. Komatsu K. Matusita 《Hyperfine Interactions》1994,94(1):2119-2124
The119Sn-Mössbauer spectra ofxSnO·(70–x)SnF2·30P2O5 glasses (0 x70) measured at 78 K comprised a doublet due to Sn2+ (=3.30–3.36 mm s–1, = 1.70–1.72 mm s–1) and a weak singlet due to Sn4+ located at –0.23 mm s–1 with respect to BaSnO3. The and of Sn2+ were comparable to those of Sn2P2O7. Small Debye temperatures (146 and 155 K) were obtained from the low-temperature measurements. These results indicate that Sn2+ and Sn4+ occupied interstitial sites, being loosely and ionically bonded to distorted PO4–x
F
x
tetrahedra. 相似文献
4.
N. Moser A. Hofmann P. Schüle R. Henes H. Kronmüller 《Zeitschrift für Physik B Condensed Matter》1988,71(1):37-42
Measurements of the complex susceptibility =–i of electron-irradiated YBa2Cu3O7– show a strong influence of the electron irradiation dose, ·t on the transition temperatureT
c
. For irradiation doses of ·t=2.2·1019 e–/cm2 we find a damage rate of T
c
/(·t)=–1.6·10–19 K/(e–/cm2). It is assumed that the decrease ofT
c
is mainly a bulk effect due to the production of atomic defects like vacancies and interstitials in the Cu–O–Cu chains and in the basal planes of the unit cells. 相似文献
5.
The measurements of diffuse reflectance spectra in the range of 400; 2500 nm and of photoacoustic spectra in the range of 350; 800 nm were used for the study of the influence of iron (III) oxide and lathanum oxide additions on the band structure of polycrystalline lead zirconate — lead titanate solid solutions. The molar ratio of zirconium and titanium in the studied solid solutions was 60 40, and the concentrations of the dopants werex FeO1.5, andy LaO1.5, werex 0; 0·05 mol, andy 0; 0·10 mol, respectively. The diffuse reflectance spectra were expressed in terms of the Kubelka-Munk function values versus incident electromagnetic radiation energy. These dependences were decomposed into partial absorption bands using a computer. Transitions of charged carriers between energy levels or bands which differ mutually by the energy of 0·9, 1·2–1·3, 1·6, 1·65–1·7, 2·4–2·5, 2·75–2·8, 2·9–3·2, 3·4–3·8 eV, were identified. Their intensities depend on the concentration of Fe and/or on La in the Pb(Zr0.60 Ti0.40) solid solutions.The authors are very grateful to Mrs. Iva Havlasová, Vra Andrsová, Ing. Jan Netuka, and Mrs. Liana Karlíková from the first authors' institute, for their technical assistance. 相似文献
6.
It is proposed that positron motion in quasiatomic positron + anion systems formed in anionic media can be described by a potential of the form Veff(r) = Zeff/r2-/r, where Zeff is the effective charge of the nucleus, and n is the effective charge of the anion. It is shown that the positron wave function of the ground state of the quasiatomic positron + anion system in the field of such a potential is X(r) = l/4·Anx·rX·e–ar. Thus the validity of selecting a test variation positron wave function (r) = l/4·A·r·e–ar is demonstrated for the potential Veff = at r = 0 and Veff = –/r for r > 0 (Gol'danskii-Prokop'ev optical positron model, Fiz. Tverd. Tela,8, 515 (1966)), belonging to the class of functions X(r). Having the wave function X(r) and Slater wave functions ns,p(r) of the electrons, annihilation photon angular distribution (APAD) curves are calculated, together with halfwidths of the APAD curves and positron lifetimes ns,p.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 52–56, May, 1990. 相似文献
7.
Tohru Koma 《Journal of statistical physics》2000,99(1-2):383-459
A two-dimensional quantum Hall system is studied for a wide class of potentials including single-body random potentials and repulsive electron–electron interactions. We assume that there exists a nonzero excitation gap above the ground state(s), and then the conductance is derived from the linear perturbation theory with a sufficiently weak electric field. Under these two assumptions, we prove that the Hall conductance
xy
and the diagonal conductance
yy
satisfy |
xy+e
2
/h|const·L
–1/2 and |
yy|const·L
–1/12. Here e
2/h is the universal conductance with the charge –e of the electron and the Planck constant h; is the filling factor of the Landau level; and L is the linear dimension of the system. In the thermodynamic limit, our results show
xy=–e
2
/h and
yy=0. The former implies that integral and fractional filling factors with a gap lead to, respectively, integral and fractional quantizations of the Hall conductance. 相似文献
8.
The crystallographic anisotropy constant K1 of monociystalline lithium ferrite films was measured by the methods of ferromagnetic resonance and rotational moments. The presence of uniaxial anisotropy in the plane of a film with the constant Ku 103 erg · cm–3 is established experimentally. The nature of the uniaxial anisotropy is explained by the anisotropy of the stresses in the plane of the film, a formula is obtained to compute the angle of deflection of the easy magnetization axis from the crystallographic direction. An estimate is made of the difference in the stresses along the axes (x–z) 1010 dyne · cm–2.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, Vol. 16, No. 9, pp. 86–89, September, 1973. 相似文献
9.
Gas formation in electrolytes with=10–2–10–4–1cm–1, distilled water = 10–5-1.5 ·10–6 –1cm–1, and chemically pure n-hexane in the initial stages of formation of discharge with rectangular voltage pulses of 0.67 and 1.85 sec duration is investigated. The experimental results are compared with the results of approximate calculations.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii Fizika, No. 11, pp. 42–47, November, 1972.The authors thank V. V. Ryumin for taking part in the discussion of the results and V. V. Lopatin for participation in the experiments with electron-optical light amplifier. 相似文献
10.
We present a method for obtaining bounds on the magnetic moment of the lepton. In order to do this, we study the radiative decayW as a function of the anomalous magnetic moment of the ,a
. One can obtain bounds as good asa
< 4.05×10–2, 2.25×10–2, 4.5×10–3, and 2.5×10–3 at the present Fermilab, future Fermilab, SSC, and LHC, respectively. 相似文献
11.
The effects of surfaces on percolation are investigated near the bulk percolation threshold ind=6– dimensions. Using field-theoretic methods, this is done within the framework of a semi-infinite continuousq-state Potts model withq1. Renormalization-group equations are obtained which imply that the usual scaling laws for surface and bulk exponents are valid to all orders in , and the surface exponents at the ordinary and special transition are computed to order . Our result for
1
ord
is in conformity with the one by Carton. 相似文献
12.
R. Oppermann 《Zeitschrift für Physik B Condensed Matter》1975,20(4):405-411
For an axially anisotropicn-vector model withm = O(n) easy – andn – m = O(n) hard components of the order parameter, we derive the susceptibility r
–1 along one of the equivalent easy axes and the perpendicular one
r
-1
toO(1/n) of the 1/n-expansion in the disordered phase. The results confirm predictions of the scaling theory, e.g.(g, t)=A t
–
X (B g/t
) and
(g, t) =A
t
–
X
(B g/t
), wheret = T – T
c
(g = 0),g is the anisotropy parameter andX, X
denote the scaling functions. We evaluate the relevant diagrams toO(1/n) which yield the coefficientsA, A
and the critical behaviour of the scaling functions and critical amplitudes explicitly for
. The extreme anisotropic case, i.e.m = O(1), is discussed briefly in the large-n limit in comparison with the mean field solution.Parts of this paper were presented at the Frühjahrstagung der Deutschen Physikalischen Gesellschaft in Freudenstadt (May 1974). 相似文献
13.
Using the DFT Becke–Lee–Yang–Parr exchangecorrelation threeparametric functional (B3LYP), we have calculated the geometry, the electron density distribution, and the vibration frequencies for pyrrole, porphin, and their 13 analogs with a regularly varying structure. It is shown that the determining role in the change in the frequencies of stretching and outofplane deformation vibrations of porphin compared to pyrrole is played by intramolecular hydrogen bonds at the porphyrin macroring center. We have separately considered and compared with the data for porphin complexes of pyrrole with different intermolecular hydrogen bonds: with an aromatic ring (NH··· cluster formed by the pyrrole selfaggregation in the liquid state) and an unshared electron pair (NH···OH2 and NH···NC4H4 clusters). The degree of participation of the NH group in the hydrogen bonds increases in the series NH··· cluster, porphin, NH···OH2 and NH···NC4H4 clusters. 相似文献
14.
We consider the directed Abelian sandpile model in the presence of sink sites whose density ft at depth t below the top surface varies as ct–. For >1 the disorder is irrelevant. For <1, it is relevant and the model is no longer critical for any nonzero c. For =1 the exponents of the avalanche distributions depend continuously on the amplitude c of the disorder. We calculate this dependence exactly, and verify the results with simulations. 相似文献
15.
S. Fujita 《Foundations of Physics》1991,21(4):439-457
If no property of a system of many particles discriminates among the particles, they are said to be indistinguishable. This indistinguishability is equivalent to the requirement that the many-particle distribution function and all of the dynamic functions for the system be symmetric. The indistinguishability defined in terms of the discrete symmetry of many-particle functions cannot change in the continuous classical statistical limit in which the number density n and the reciprocal temperature become small. Thus, microscopic particles like electrons must remain indistinguishable in the classical statistical limit although their behavior can be calculated as if they move following the classical laws of motion. In the classical mechanical limit in which quantum cells of volume (2)3 are reduced to points in the phase space, the partition functionTr{exp(–) for N identical bosons (fermions) approaches (2)–3N(N!) ... d3r1 d3p1 ... d3rN d3pN
exp(–H). The two factors, (2)–3N and (N!)–1, which are often added in anad hoc manner in many books on statistical mechanics, are thus derived from the first principles. The criterion of the classical statistical approximation is that the thermal de Broglie wavelength be much shorter than the interparticle distance irrespective of any translation-invariant interparticle interaction. A new derivation of the Maxwell velocity distribution from Boltzmann's principle is given with the assumption of indistinguishable classical particles. 相似文献
16.
A full set of spectra of the optical functions of a zinc oxide crystal in the range 0–30 eV has been calculated on the basis of the experimental spectrum of characteristic losses –Im –1. The 2, 1 and Im –1, Re –1 spectra were decomposed into elementary components. The most intense transverse and longitudinal components of transitions and their parameters have been determined. The data obtained were compared with theoretical calculations of the bands. 相似文献
17.
Manaa H. Henari Fryad Z. Al-Saie Ahmed Maier Stefanie Blau Werner J. 《Optical and Quantum Electronics》2004,36(9):819-826
We report optical gain measurements in four different copolymers polyp-phenylene-co-[2,5-dioctyloxy-p-phenylene-bis-2(4-nonyl phenyl) vinylene]nonyl-PpPV, polym-phenylene-co-[2,5-dioctyloxy-p-phenylene-bis-2(4-methyl phenyl) vinylene]methyl-PmPV, polyp-phenylene-co-[2,5-dioctyloxy-p-phenylene-bis-2(4-methyl-phenyl) vinylene]methyl-PpPV, polyp-phenylene-co-[2,6-naphthylene-bis-2(4-nonyl phenyl) vinylene]nonyl-PpPV-NV in toluene. The copolymers are related to poly(phenylene vinylene) and have been synthesized via Horner–Emmons polycondensation reaction. The optical gain determined from the amplified spontaneous emission (ASE) intensity is dependent on the excited stripe length. The net optical gain coefficients are found to vary between 0.1 cm–1 in nonyl-PpPV to 2.5 cm–1 in methyl-PmPV under nanosecond pulse excitation. The gain for Rodamine 6G was also measured under the same experimental condition and was used to determine the stimulated emission cross-sections for the four polymers and found to be SE(peak)= 6.7 × 10–20 cm2 for nonyl-PpPV, SE(peak)= 1.7 × 1018 cm2 for methyl-PmPV, SE(peak)= 1.4 × 10–18 cm2 for methyl-PpPV, and SE(peak)= 1.5 × 10–18 cm2 for nonyl-PpPV-NV. 相似文献
18.
V. N. Fetisov L. Majling J. Žofka R. A. Eramzhyan 《Czechoslovak Journal of Physics》1986,36(3):451-454
The applicability of (K
–,–) - and (K
–,–
N)-reactions on13,14C and14,15N nuclei to the study of -transitions in primary and daughter -hypernuclei is discussed. The intensity of -deexcitation of
13C state |S
12C(15·11 MeV; 1+1): 1/2+ has been shown to be comparable with the intensity of baryon decay. Isospin selection rules are used to distinguish excitation energy ranges of primary hypernuclei, where the identification of the secondary -lines is probable.Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985. 相似文献
19.
F. V. Adamian G. G. Akopian H. H. Vartapetian P. I. Galumian V. H. Grabsky V. V. Karapetian G. V. Karapetian V. K. Oktanian 《Czechoslovak Journal of Physics》1986,36(8):945-947
The beam asymmetryB has been measured for the reactiond pn in the energy rangeE
= 0·4 ÷ 0·8 GeV and angles
p
cm
= 45 ÷ 95° and ford 0d at energiesE
=0·5, 0·6, 0·7 GeV and angle
cm
= 130°. The results obtained are compared to existing theoretical predictions which take into account the possible contribution of dibaryon resonances.Presented at the symposium Mesons and Light Nuclei, Bechyn, Czechoslovakia, May 27–June 1, 1985. 相似文献
20.
On the mechanism of the induced anisotropy of magnesium ferrites in the range of higher temperatures
R. Gerber 《Czechoslovak Journal of Physics》1968,18(9):1204-1210
A simple mechanism explaining not only the magnitude but also the type of induced anisotropy on the magnesium ferrite Mg0·78 Fe2·22 O4·026 in the temperature range from 400 to 500°K has been designed. The experimentally estimated values of the microscopic bond energyl
p 7×10–16 erg of the configuration contributing to theF-type anisotropy and the activation energy exp = 1·1 eV are in good correspondence with the valuesl
d1·6×10–16erg and cal = 1·15 eV which have been calculated theoretically.Dedicated to Professor Dr. Jaromír Bro on his sixtieth birthday.The author would like to express his thanks to Dr. S. Krupika for valuable discussions and his interest in this paper. 相似文献