ISSN:0370-1972    

DOI:10.1002/pssb.2221380251

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221380252

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221380253

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe energies of reconstructed structures of symmetrical 〈011〉 tilt grain boundaries with θ>70.53° in silicon are calculated using the tight‐binding type electronic theory (bond orbital model). The energies of the most stable reconstructed boundary structures are in the same range or a little larger than those with θ ≦ 70.53°. These reconstructed structures are more stable than those with dangling bonds. There exists the continuity of boundary structure in the range 70.53° ≦ θ ≦ 148.41° (Σ = 27). Shallow cusps in the energy against θ curve can be found at special boundaries of type Σ = 3 (θ = 109.47°), Σ = 11 (θ = 129.52°), and Σ = 27 (θ = 148.41°), all of which are composed of one kind of original patterns. For θ>148.41°, boundary structures are composed of an ar

ISSN:0370-1972    

DOI:10.1002/pssb.2221380202

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractAn expression for the order–disorder transformation temperature in substitutional alloys of AB3‐type is determined in terms of the classical theory of ordering in alloys with low impurity concentration. The order–disorder transformation temperature is shown to increase at the initial stages of alloying at any relations of ordering energies. The data on theoretical calculations are compared with experimental ones obtained with Ni3Fe alloy doped by different impurities. Much consideration is given to results obtained with Ni3(Fe1−xMnx) alloys. Using neutron diffraction analysis, the lack of Ni24Fe4Mn4ternary superstructure is shown, and theTK(x) dependence with the extremum atx≈ 0.4 is obtained from dilatometric and specific heat me

ISSN:0370-1972    

DOI:10.1002/pssb.2221380203

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA phenomenological model for the lattice dynamics of face centred cubic transition metals is developed. The potential energy of the crystal lattice is considered as due to (i) ion–ion and (ii) ion–electron interactions. The force‐field involving ion–ion interaction is essentially a three body force model employing valence force field approximations. The contribution to the potential energy from ion–electron interaction is considered by a screened Coulomb potential. Phonon dispersion curves, specific heat, and Debye characteristic temperature of nickel, palladium, and thorium are computed on the basis of the model developed. Computed results are compared with the experime

ISSN:0370-1972    

DOI:10.1002/pssb.2221380204

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe system is considered of Ising‐like chains suffering the antiferroelectric instability. The interaction between the chains is taken into account within the framework of the molecular field approximation. Then summing over states of a single chain is carried out by the method making immediately use of the fact that the unit cell can consist of several atoms. Such an approach may sometimes be more convenient than the transfer‐matrix method. An appropriate phase diagram in an uniform external field is investigated. As a result, the electrical effects essentially must be small so that the corresponding measurements will be difficult in such systems. As an example the TlHF2structure is discus

ISSN:0370-1972    

DOI:10.1002/pssb.2221380205

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractStatic dislocation scattering processes result in an additional phonon scattering term because of the simultaneous presence of the impurity–phonon scattering processes. The additional term of the inverse of relaxation time is calculated by using the perturbation and is found to be proportional to the square of the phonon frequency. Excellent agreement is obtained between theory and experimental results of the phonon conductivity of the plastically deformed LiF crystal

ISSN:0370-1972    

DOI:10.1002/pssb.2221380206

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe improved unsymmetrized self‐consistent field method developed in preceding papers is used to study anharmonic effects in imperfect crystals. Various one‐dimensional models of anharmonic crystals with defects are considered: vacancy, free surface, adsorption with taking into account the influence of adatoms on the adsorbent, and substitutional impurities. The formulae for the lattice relaxation near defects, for the effective amplitudes of the anharmonic vibrations of atoms, and for the Helmholtz free energy are obtained. They are expressed in terms of the nearest‐neighbour interaction potentials and their derivatives of several orders at the equilibrium points. A comparison with known results for some harmonic models is made. The decisive role of the anharmonicity in such effects as the temperature dependence of the lattice relaxation and the influence of the imperfections on thermal properties of crystals is emphasized. The possibility of application of the method to three‐dimensional imperfect crystals, as well as of taking into consideration the interactions with next neighbours i

ISSN:0370-1972    

DOI:10.1002/pssb.2221380207

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractWhen a solid is subject to an intense electronic excitation, it is expected that its cohesive properties differ from the non‐excited state. The variation of crystal instability temperature,Tc, with the concentration of excited electron–hole pairs is examined theoretically. Using a phenomenological model of electron–phonon–defect interactions, it is shown thatTcdecreases quasi‐linearly with increasing electron–hole pair density. The consequences of this on diffraction broadening, threshold energy for transformation, premelting, and optical properties ar

ISSN:0370-1972    

DOI:10.1002/pssb.2221380208

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY