Specific heat capacity of molybdenum chalcogenides. V. An investigation of the heat capacity of PbMo6S8, PbMo6Se8, and corresponding samples with depressed T cvalues

Alekseevskiǐ, N. E.; Wolf, G.H.; Hohlfeld, C.; Добровольский, Николай Михайлович

doi:10.1007/bf00119518

Cited by 10 publications

(1 citation statement)

References 17 publications

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“…Varieties of materials exhibit this βγ-change: examples include group V transition metals V, Nb and Ta (Fig. 1) [2][3][4][5] the Chevrel phases PbMo 6 X 8 (X=S, Se), 6,7 the A12-type Re 3 W, 8 the A15-type Nb 3 Sn and V 3 Si (Fig. 2), 9,10 the layered NbSe 2 , 11 the perovskite MgCNi 3 (Fig.…”

Section: Introductionmentioning

confidence: 99%

On the anomalous thermal evolution of the low-temperature, normal-state specific heat of various nonmagnetic intermetallic compounds

ElMassalami¹

2011

Preprint

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The low-temperature normal-state specific heat and resistivity curves of various nonmagnetic intermetallic compounds manifest an anomalous thermal evolution. Such an anomaly is exhibited as a break in the slope of the linearized C/T versus T 2 curve and as a drop in the R versus T curve, both at the same T βγ . It is related, not to a thermodynamic phase transition, but to a Kohn-type anomaly in the density of states curves of the phonon or electron subsystems. On representing these two anomalies as additional Dirac-type delta functions, situated respectively at kBθL and kBθE, an analytical expression for the total specific heat can be obtained. A least-square fit of this expression to experimental specific heat curves of various compounds reproduced satisfactorily all the features of the anomalous thermal evolution. The obtained fit parameters (in particular the Sommerfeld constant γ0 and Debye temperatures θD) compare favorably with the reported values. Furthermore, the analysis shows that (i) T βγ /θL = 0.2 1 ± 1/ √ 6 and (ii) γ0 ∝ θ −2 D ; both relations are in reasonable agreement with the experiments. Finally, our analysis (based on the above arguments) justifies the often-used analysis that treats the above anomaly in terms of either a thermal variation of θD or an additional Einstein mode.

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Section: Introductionmentioning

confidence: 99%

On the anomalous thermal evolution of the low-temperature, normal-state specific heat of various nonmagnetic intermetallic compounds

ElMassalami¹

2011

Preprint

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Influence of the Phonon Frequency Dispersion on the Critical Temperature of Superconductors

Iordatii¹,

Kon²

1982

Physica Status Solidi (b)

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The dependence of the superconductor critical temperature (T ) on the conduction electron concentration is investigated by means of the Eliashberg equations /l/. Two cases a r e considered: 1 ) the "jellium" model, 2) the electron-phonon interaction. C The Tc calculation in the first case differs from earlier calculations (see, for example,/2/) by our taking into account the equation for the renormalizatioii parametar Z~W,). ed by two branches: a high -frequency branch with acoustic law of dispersion and an Einstein low-frequency branch which is e.g. present in ternary molybdenum chalcogenides /3/.In the second case it is supposed that the phonon spectrum can be approximat-2 2 The critical temperature Tc is found as a function of OL = xTF/4pF for various Einstein frequencies (ae is a reciprocal Thomas-Fermi screening radius, pF Fermi momentum of conduction electrons). The dependence of interaction on the transferring momentum q is taken into account. After performing the integration over < ( 5 = k /2m -k2d2m) the equations for the energy gap A(w ) and renormalization parameter z(on) in the case of intermediate connection /4/ can by reduced as:T F 2 n 1 ) Akademicheskaya 5, 2 77028 Kishinev-2 8, USSR.

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Flükiger¹,

Wolf²

O (Without Cuprates) - Sc

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Specific heat capacity of molybdenum chalcogenides. V. An investigation of the heat capacity of PbMo6S8, PbMo6Se8, and corresponding samples with depressed T cvalues

Cited by 10 publications

References 17 publications

On the anomalous thermal evolution of the low-temperature, normal-state specific heat of various nonmagnetic intermetallic compounds

On the anomalous thermal evolution of the low-temperature, normal-state specific heat of various nonmagnetic intermetallic compounds

Influence of the Phonon Frequency Dispersion on the Critical Temperature of Superconductors

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