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1.
The evolution of the surface morphology of LPCVD poly-Si films (deposition temperature 620°C), a-Si films (deposition temperature 550°C) and poly-Si films, obtained by the crystallization of a-Si is investigated in the thickness range 40–500 nm. It is found that upon an increase in the thickness from 40 to 500 nm, the surface roughness (parameters S q , S z , S v ) is increased for poly-Si, while in the case of a-Si and poly-Si obtained by crystallization a-Si, on the contrary, decreases. The correlation length (S al ) increases for all three types of silicon films. Poly-Si films, obtained by the crystallization of a-Si, as compared to LPCVD poly-Si films have a significantly lower surface roughness, respectively, S q two times less at a thickness of 40 nm and sixteen times less at 500 nm. In contrast to thick films, thin a-Si films (at thicknesses of less than 40 nm) have a granular structure, which is especially pronounced at an average thickness of about 20 nm and there is a maximum on the dependence of the roughness S q on the thickness.  相似文献   

2.
A. A. Bykov 《JETP Letters》2009,89(11):575-578
The effect of millimeter microwave radiation on the electron transport of two-dimensional (2D) ballistic microbars formed on the basis of individual GaAs quantum wells at a temperature of T = 4.2 K in magnetic fields B < 0.6 T has been investigated. Differences have been revealed in the magnetic field dependences of the microwave photoresistance of a 2D electron gas in Hall bars with a length L and a width W for the cases L, W > l p and L, W < l p , where l p is the electron mean free path for momentum. The microwave photoresistance in macroscopic bars (L, W > l p ) is a periodic alternating function of the inverse magnetic field; in microbars (L, W < l p ), it is a periodic positive function of 1/B. The experimental results indicate that the mechanisms of the microwave photoresistance of a 2D electron gas are different for macroscopic and microscopic bars.  相似文献   

3.
Fermionic and weak decays of the scalar leptoquarks S = S 1 (+) , S 1 (?) , and S m and the scalar gluons F = F 1 and F 2 predicted by the minimal model involving four-color symmetry and the Higgs mechanism of quark-and lepton-mass splitting are considered. The widths and the branching ratios are calculated for these decays, and the results are analyzed versus the couplings and masses of decaying particles. It is shown that, at relatively small mass splittings Δm within scalar doublets (Δm < m W), the fermionic decays S 1 (+) tl j + , S 1 (?) v i \(\tilde b\), S mt \(\tilde \nu \) j, F 1t \(\tilde b\), and F 2t \(\tilde t\), which are characterized by few-GeV widths for m S, m F < 1 TeV and decay branching ratios close to unity, are dominant, but that, for Δm > m W, the weak decays SS′W and FF’W compete with the above fermionic decays. In the case of m S < m t, the processes S 1 (+) cl j + , S 1 (?) v i \(\tilde b\), S mbl j + , and S mc \(\tilde \nu \) j, whose total branching ratios are Br(S 1 (+) cl +) ≈ Br(S 1 (?) v \(\tilde b\)) ≈ 1, Br(S mbl +) ≈ 0.9, and Br(S mc \(\tilde \nu \)) ≈ 0.1, appear to be dominant decays of scalar leptoquarks. Searches for these decays at LHC and the Tevatron are of interest.  相似文献   

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The critical current I c of S-(FN)-S Josephson structures has been calculated as a function of the distance L between superconducting (S) electrodes using the Usadel quasiclassical equations for the case of specifying the supercurrent in the direction parallel to the interface between the ferromagnetic (F) and normal (N) films of the composite weak-link region. It has been shown that, owing to the interaction between F and N films, both the typical decrease scale I c(L) and the period of the critical current oscillations can be much larger than the respective quantities for the SFS junctions. The conditions have been determined under which these lengths are on the order of the effective depth ζN of superconductivity penetration to a normal metal.  相似文献   

6.
The dynamic scaling behaviors of the restricted-solid-on-solid (RSOS) model on two new types of substrate, which are honeycomb and square-octagon lattice substrates, are studied by means of Kinetic Monte Carlo simulations. The growth exponent β and the roughness exponent α defined, respectively, by the surface width via W ~ t β and the saturated width via W sat ~ L α , L being the system size, were obtained by a power-counting analysis. Our simulation results show that the Family-Vicsek scaling is still satisfied. However, the structures of the substrates indeed affect the dynamic behavior of the growth model. The values of the roughness exponents fall between regular and fractal lattices. Deeper analysis show that the coordination number of the substrates play an crucial role.  相似文献   

7.
The electronic—vibrational fluorescence spectra of the first, S01Lb, and second, S01La, electronic transitions of 7-azaindole and its tautomer for an isolated state have been calculated. Specific features of structural changes in 7-azaindole and its tautomer upon electronic excitation are determined. Vibrational spectra are assigned for the ground state, and the vibrational structure of fluorescence spectra is interpreted. It is shown that the intensity redistribution between the 6a and 6b oscillations, which is observed in the fluorescence spectrum of the S01Lb transition in 7-azaindole, can be explained as a result of intensity borrowing (according to the Herzberg—Teller mechanism) from the 1La state.  相似文献   

8.
After a short review of the present situation of the quantum theory of measurement, a formulation of the measuring process is given, which allows an “objective” interpretation. Starting from the unitary time transformation of the states of the measured systemS and the measuring deviceM, it is shown that after appropriate specification of the interaction HamiltonianH int betweenS andM and the macroscopic structure ofM, the statistical operatorW ofS+M approximately develops into the mixture, which is desired as result of the measuring process. During the process the interference terms practically vanish in the sense of weak operator convergence, while on the other hand their Hilbert-Schmidt norm remains constant.  相似文献   

9.
In recent years, a sufficient condition for determining chaotic behaviours of the non-linear systems has been characterized by the negative Schwarzian derivative (Hac?bekiro?lu et al, Nonlinear Anal.: Real World Appl. 10, 1270 (2009)). In this work, the Schwarzian derivative has been calculated for investigating the quantum chaotic transition points in the high-temperature superconducting frame of reference, which is known as a nonlinear dynamical system that displays some macroscopic quantum effects. In our previous works, two quantum chaotic transition points of the critical transition temperature, T c, and paramagnetic Meissner transition temperature, T PME, have been phenomenologically predicted for the mercury-based high-temperature superconductors (Onba?l? et al, Chaos, Solitons and Fractals 42, 1980 (2009); Aslan et al, J. Phys.: Conf. Ser. 153, 012002 (2009); Çataltepe, Superconductor (Sciyo Company, India, 2010)). The T c, at which the one-dimensional global gauge symmetry is spontaneously broken, refers to the second-order phase transition, whereas the T PME, at which time reversal symmetry is broken, indicates the change in the direction of orbital current in the system (Onba?l? et al, Chaos, Solitons and Fractals 42, 1980 (2009)). In this context, the chaotic behaviour of the mercury-based high-temperature superconductors has been investigated by means of the Schwarzian derivative of the magnetic moment versus temperature. In all calculations, the Schwarzian derivatives have been found to be negative at both T c and T PME which are in agreement with the chaotic behaviour of the system.  相似文献   

10.
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A version of the solution of the problem of simultaneous determination of the structure and characteristics of a two-dimensional signal and of two-dimensional complex transfer or instrumental functions is considered. The solution is based on measurements of four independent intensity distributions for spectral representation of a signal: Isr(Wx, Wy) for a signal subjected to the transfer function, Ismrn(Wx, Wy) for a signal affected by additional specially produced modulation and the transfer function, Isrn(Wx, wy) for a signal of the form Isr(Wx, Wy) with a certain additional modulation at the output, and /5mm(wx,u/y) for a signal of the form Ismr(Wx, Wy) with a certain additional modulation at the output. The intensity distributions obtained in the work make it possible to calculate the amplitude and phase components of the signal being analyzed and the transfer function. Additional modulations should provide visualization of phase information in one form or another.Linear amplitude modulation, which represents a particular form of spatial modulation, is analyzed. For this case, concrete expressions making it possible to calculate the amplitude and phase characteristics of the spectra of the signal being analyzed and the transfer function and, therefore, the characteristics of both the signal itself and the transfer function are obtained.  相似文献   

13.
Given two weighted graphs (X, bk, mk), k =?1,2 with b1b2 and m1m2, we prove a weighted L1-criterion for the existence and completeness of the wave operators W±(H2, H1, I1,2), where Hk denotes the natural Laplacian in ?2(X, mk) w.r.t. (X, bk, mk) and I1,2 the trivial identification of ?2(X, m1) with ?2(X, m2). In particular, this entails a general criterion for the absolutely continuous spectra of H1 and H2 to be equal.  相似文献   

14.
Thin films of chalcogenide glasses deposited on quartz glass substrates by thermal evaporation in vacuum have been investigated. The dependences n(λ) and k(λ) for films of different composition have been determined from the transmission spectra. Expressions of the n = A + BL + CL 2 + 2 + 4 type (L = (λ 2 ? 0.028)?1 and A, B, C, D, and E are constants) for calculating the refractive indices of As2Se3, AsSe4, AsS4, and AsS16.2Se16.2 films in the wavelength range from 0.5 to 2.5 μm are reported.  相似文献   

15.
TheL-subshell andM conversion coefficients ratios of the 2+→0+ transitions in some deformed even-even nuclei have been determined using a high resolution iron free double focusing beta-ray spectrometer. All possible uncertainties in these measurements have been minimized and properly evaluated. TheL 1+L 11/L 111 ratios for the 2+→0+ E2 transitions in Dy160, Er166, Yb170, Hd176 and W182 are found to be in agreement with the theoretical ones within an experimental error of about 4%. However, large deviations from the theory of about two order of magnitude are observed forL/M conversion ratios. The deviations indicate the possibility of considerable approximation in the theoretical calculation of theM-internal conversion coefficients.  相似文献   

16.
We use the results for the structure function FL for a gluon target with a nonzero transverse momentum squared at the order αs, obtained in our previous paper, for comparison with recent H1 experimental data for FL at fixed W values and with collinear GRV predictions in the leading-order and next-to-leading-order approximations.  相似文献   

17.
The thermoolectric powerS and the electrical conductivity σ of amorphous AuxSb100-x and CuxSb100-x films have been measured in the temperature range between about 2 K and 350 K for concentrations close to the eetal-insulator transition. In both systems the transition occurs at a critical concentrationx c≈8 at.% noble metal content. A characteristic feature of the transition is in both cases a strong increase of the low temperature slope of the thermopower, i.e.S/T| t»0 , when approachingx c from the metallic side. The results are compared with different theoretical predictions for the metal-insulator transition. Furthermore we report on the changes ofS and σ during annelaing. It will be shown that especiallyS(T) of the samples withx close tox c depends strongly on the annealing state of the films.  相似文献   

18.
The photoinduced semiconductor-metal phase transition occurring for a time Δt < 1 ps in the surface layer of vanadium dioxide is studied theoretically. A nonthermal mechanism of instability development is considered. An equation for the order parameter ξ of the photoinduced semiconductor-metal phase transition is derived. It is shown that the transition of the surface layer of VO2 to the metallic state requires irradiation by a laser pulse whose energy density W exceeds a critical value W c. The phase transition is initiated at the surface, after which the interface propagates deep into the sample. The critical energy density W c, the velocity of propagation of the metal-semiconductor interface, the thickness z 0, and the characteristic time Δt of formation of the metal layer are calculated. The theoretical results obtained are in agreement with the experimental data on irradiation of vanadium dioxide single crystals by high-intensity laser pulses.  相似文献   

19.
The correlation between the asymptotic normalization constant for the deuteron, AS, and the neutron-proton scattering length for the triplet case, at, is investigated. It is found that 99.7% of the asymptotic constant AS is determined by the scattering length at. It is shown that the linear correlation between the quantities A S ?2 and 1/at provides a good test of correctness of various models of nucleon-nucleon interaction. It is revealed that, for the normalization constant AS and for the root-mean-square deuteron radius rd, the results obtained with the experimental value recommended at present for the triplet scattering length at are exaggerated with respect to their experimental counterparts. By using the latest experimental data obtained for phase shifts by the group headed by Arndt, it proved to be possible to derive, for the low-energy parameters of scattering (at, rt, Pt) and for the properties of the deuteron (AS, rd) results that comply well with experimental data.  相似文献   

20.
The proton-antiproton annihilation at rest into two mesons is calculated by two methods: (i) on the basis of theSU 6 -covariantS-matrix formalism recently proposed byRothleitner andStech, and (ii) by assuming the additional invariance under the group (SU 6) W proposed byLipkin andMeshkov. In the first case the calculations give only few relations between transition amplitudes, whereas the larger symmetry group (SU 6) W actually determines all amplitudes up to a common factor. While agreement with experiment seems to be poor in some cases for the (SU 6) W , so far there are no experimental data available to test the relations of case (i).  相似文献   

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