Electron transport in the carbon-copper nanocluster structure
Tóm tắt
The electron transport in hydrogenated amorphous carbon films a-C: H with copper nanocluster inclusions has been investigated. The conditions of cluster formation are derived. It is theoretically demonstrated that the energy band structure of the matrix substantially affects the conditions of cluster formation. The electron transport depends on the cluster structure. It is found that, below the percolation threshold (the case of isolated clusters), the transport current is governed by two components depending on the electric field strength. At low field strengths, the current is caused by electrons in the conduction band of amorphous carbon, which are thermally excited from copper clusters. At high field strengths, the transport current is provided by tunneling electrons from the Fermi level of copper clusters to the conduction band of a-C: H. The difference between the mobility edge of the conduction band of amorphous carbon and the Fermi level in copper clusters is determined from the temperature dependence of the resistance and proves to be equal to 0.48 eV. The temperature dependences of the resistance at low field strengths exhibit a fine structure. It is revealed that, above the percolation threshold, the electrical resistance of clusters is considerably contributed by the residual resistance, which is supposedly associated with the electron scattering by cluster surfaces. The temperature effect on the electron transport is examined using the spin-wave scattering technique at a frequency of 4.0 GHz. It is found that the spin wave in the yttrium iron garnet (YIG) film is predominantly affected by thermally excited electrons located above the mobility edge in the conduction band of a-C: H.
Tài liệu tham khảo
J. Robertson, Adv. Phys. 35(4), 317 (1986).
V. I. Ivanov-Omskii, A. B. Lodygin, and S. G. Yastrebov, Fiz. Tverd. Tela (S.-Peterburg) 37(6), 1693 (1995) [Phys. Solid State 37 (6), 920 (1995)]; V. I. Siklitsky, S. G. Yastrebov, and A. B. Lodygin, Chaos, Solitons and Fractals 10 (12), 2067 (1999).
V. I. Ivanov-Omskii, V. I. Siklitskii, and S. G. Yastrebov, Fiz. Tverd. Tela (S.-Peterburg) 40(3), 568 (1998) [Phys. Solid State 40 (3), 524 (1998)].
A. I. Ansel’m, Fundamentals of Statistical Physics and Thermodynamics (Nauka, Moscow, 1973).
A. S. Davydov, Quantum Mechanics (Nauka, Moscow, 1973).
N. F. Mott and E. A. Davis, Electronic Processes in Non-Crystalline Materials (Clarendon Press, Oxford, 1979; Mir, Moscow, 1982).
B. I. Shklovskii and A. L. Efros, Electronic Properties of Doped Semiconductors (Nauka, Moscow, 1979; Springer-Verlag, New York, 1984).
B. Abeles, Ping Sheng, M. D. Coutts, and Y. Arie, Adv. Phys. 24(3), 407 (1975).
B. M. Smirnov, Physics of Fractal Clusters (Nauka, Moscow, 1991).
P. S. Kireev, Physics of Semiconductors (Vysshaya Shkola, Moscow, 1975).
L. D. Landau and E. M. Lifshitz, Quantum Mechanics: Non-Relativistic Theory (Nauka, Moscow, 1974, 3rd ed.; Pergamon Press, Oxford, 1977, 3rd ed.).
E. M. Lifshitz and L. P. Pitaevskii, Physical Kinetics (Nauka, Moscow, 1979; Pergamon Press, Oxford, 1981).
A. A. Abrikosov, Fundamentals of the Theory of Metals (Nauka, Moscow, 1987; North-Holland, Amsterdam, 1988).
Physical Quantities, Ed. by I. S. Grigor’ev and E. Z. Meilikhov (Énergoatomizdat, Moscow, 1991).
A. S. Davydov, Theory of the Solid State (Nauka, Moscow, 1976).
P. M. Platzman and P. A. Wolff, Wave and Interactions in Solid State Plasmas, Suppl. 13 (Academic Press, New York, 1973), translated under the title Volny i vzaimodeistvie v plazme tverdogo tela (Mir, Moscow, 1975).