Propriétés électroniques dans les solides désordonnés. III. Les mécanismes de transport par saut faisant appel aux modèles des paires et à la conduction par polarons

Thermoelectric, transport, and magnetic properties of the polaron semiconductorFexCr3−xSnyder1, Caillat2, Fleurial3 2000Phys. Rev. B551270View full textAdd to dashboardCite

“…The data closely correspond to exp(1/T 1/4 ) ͑Fig. 3͒, which is expected for phonon assisted hopping of small polarons 16 ͑as well as variable range hopping͒. The phonon-assisted hopping mechanism is expected to dominate at temperatures less than half the Debye temperature.…”

High-temperature thermopower inLa2/3Ca1/3Jaime1, Salamon2, Rubinstein3 et al. 1996Phys. Rev. B358121471View full textAdd to dashboardCite

“…Combining that value with expressions for E p in Ref. 12 , we obtain the relation m * /m e = Ar −2 p between the effective mass of carriers m * and the polaron radius, with A = 1.9 nm 2 . This gives, for example, a value m * /m ≈ 3 when r p is of the order of two cell parameters.…”

“…[10][11][12] In a parallel development, Kasuya peratures, where k B T ≤ 10 −4 eV , the only possible mechanism is QT between neighboring distortions. As the temperature is raised, but for T ≤ θ D /2, half the Debye temperature, phonon assisted hopping dominates producing a conductivity σ ∝ exp(−T −1/4 ); this is not, however, associated with variable range hopping.…”

Strong influence of theMn3+content on the binding energy of the lattice polarons in manganese perovskites

“…A certain type of localization energy must be provided in order to localize the electron as a lattice polaron. 15 Transport measurements in these manganites [3][4][5][6] indicate that Ca-based manganites can be described in the paramagnetic regime with Holstein's model for small polarons in molecular materials in the adiabatic regime. In this case, the localization energy is provided by the interaction of the electron with an optic phonon mode.…”

“…0 can be obtained from the dependence of thermopower with temperature. 5,15 In this article we will make use of the thermopower data obtained by Palstra We have performed resistance measurements in the oxygen-deficient films. We will show results for temperatures below ϳ350 K because we observed that above such a temperature the films start to recover the expelled oxygen ͑to be published elsewhere 25 ͒.…”