Hopping Conductivity in Granular Metals
نویسندگان
چکیده
)Work supported by the National Science Foundation. *Alfred P. Sloan Research Fellow. E. F. Gross, Vsp. Fiz. Nauk 76, 433 (1962), and 103, 431 (1971) [Sov. Phys. Usp. 5, 195 (1962) and 14, 104 {1971)). A. Compaan and H. Z. Cuxnmins, Phys. Rev. B 6, 4753 (1972). Y. Petroff, P. Y. Yu, and Y. B. Shen, Phys. Bev. Lett. 29, 1558 (1972). P. Y. Yu, Y. R. Shen, Y. Petroff, and L. M. Falicov, Phys. Rev. Lett. 30, 283 (1973). E. F. Gross, A. G. Zhilich, B. P. Zakharchenya, and A. V. Varfalomeev, Fiz. Tverd. Tela 3, 1445 (1961) [Sov. Phys. Solid State 3, 1048 (1961)j. S. Nikitine, J. B. Grun, and M. Certier, Phys. Kondens. Mater. 1, 214 (1963). W. S. Brower, Jr., and H. S. Parker, J. Cryst. Growth 8, 227 (1971). A. Compaan and H. Z. Cummins, Bull. Amer. Phys. Soc. 18, 75 (1973). Air Products and Chemicals, Inc. , Allentown, Pa. The data points in Fig. 2 indicate the observed Raman intensity divided by the incident laser power. Absorption corrections, which are less than 4' in this frequency range, have not been included. B. Loudon, Advan. Phys. 13, 423 (1964); J. L. Birman, "Theory of Crystal Space Groups and Infra-Bed and Raman Processes in Insulating Crystals" in Handbuch der Physik, edited by S. Flugge (Springer, New York, 1973, to be published), Vol. 25, Part 2b. ' See, for example, M. Born and M. Bradburn, Proc. Roy. Soc., Ser. A 188, 161 (1947); L. N. Ovander, Opt. Spectrosk. 9, 571 {1960) [Opt. Spectrosc. 9, 302 (1960)] . '3J. L. Birman, to be published. P. F. Williams and S. P. S. Porto, Bull. Amer. Phys. Soc. 18, 411 (1973); P. F. Williams, Ph. D. thesis, University of Southern California, 1973 {unpublished) . P. Y. Yu, Y. R. Shen, and Y. Petroff, Bull. Amer. Phys. Soc. 18, 411 (1973). R. M. Martin, Phys. Rev. B 4, 3676 (1971).
منابع مشابه
Cotunnelling and polaronic effect in granular systems
We theoretically study the conductivity in arrays of metallic grains due to the variable-range multiple cotunneling of electrons with short-range (screened) Coulomb interaction. The system is supposed to be coupled to random stray charges in the dielectric matrix that are only loosely bounded to their spatial positions by elastic forces. The flexibility of the stray charges gives rise to a pola...
متن کاملThermal transport in granular metals
– We study the electron thermal transport in granular metals at large tunnel conductance between the grains, gT 1, and not too low a temperature, T > gTδ, where δ is the mean energy level spacing for a single grain. Taking into account the electron-electron interaction effects, we calculate the thermal conductivity and show that the Wiedemann-Franz law is violated for granular metals. We find t...
متن کاملGiant Hall effect in superparamagnetic granular films
A comprehensive review of the giant Hall effect (GHE) is presented, with emphasis on novel experimental data obtained in Ni–SiO2 and Co–SiO2 films prepared by co-sputtering. GHE is observed close to and on both sides of the metal–insulator transition. From the point of view of microscopic conduction mechanisms, this means a crossover from metallic conductivity with weak localization to tunnelin...
متن کاملHopping Conductivity in Single Crystals (Cd0.6Zn0.32Mn0.08)3As2 (RESEARCH NOTE)
The growth processes of Tetragonal single crystals of solid solution (Cd0.6Zn0.32Mn0.08)3As2, space group P42/nmc, has been synthesized by Bridgman method. Conductivity and magnetoresistance of (Cd0.6Zn0.32Mn0.08)3As2 were measured in the range 1.6K to 300K and in magnetic field up to 25 T. Crossover from Mott variable-range-hopping conductivity mechanism close to helium temperatures. In this w...
متن کاملUniversality of the electrical transport in granular metals
The universality of the ac electrical transport in granular metals has been scarcely studied and the actual mechanisms involved in the scaling laws are not well understood. Previous works have reported on the scaling of capacitance and dielectric loss at different temperatures in Co-ZrO2 granular metals. However, the characteristic frequency used to scale the conductivity spectra has not been d...
متن کاملUniversal description of granular metals at low temperatures: Granular Fermi liquid
Granular metals exhibit a wealth of behaviors generic to strongly interacting disordered electronic systems and offer a unique experimental tool for studying the interplay between the effects of disorder and interactions. Depending on the strength of coupling between the grains these systems can assume either insulating or metallic phases. Remarkably, metallic samples exhibit qualitatively diff...
متن کامل