Surface roughness and size effects of thin gold films on mica

Muñoz RC; Concha, A.; Mora, F; Espejo, R.; Vidal G.; Mulsow, M; Arenas, C.; Kremer, G; Moraga L.; Esparza R.; Haberle, P.


We report measurements of the topography of a gold film deposited on a mica substrate using scanning tunneling microscope (STM), and measurements of the conductivity sigma of the film performed between 4 and 300 K. From images obtained with the STM running in air in the constant current mode of a gold sample 70-nm-thick deposited under UHV on a mica substrate preheated to 300 OC, we compute the average autocorrelation function (ACF) that characterizes the surface of the film in the scale of 10x 10 nm(2), and determine by least-squares fitting the parameters delta (rms. amplitude) and xi (lateral correlation length) corresponding to an exponential that best describes the average ACF data. Using an exponential representation of the ACF, the parameters delta and xi determined from STM measurements, and a modified version of the theory of Sheng, Xing, and Wang recently proposed [R. C. Munoz et al., J. Phys.: Condens. Matter 11, L299 (1999)], we calculate the temperature dependence of the bulk resistivity rho(0)(T) and of the increase in resistivity Delta rho(T)=rho(T)-rho(0)(T) induced by electron-surface scattering on this film. The result is that 1-sigma/sigma(0)=1-rho(0)/rho=Delta rho/rho amounts to about 2.6% at 300 K, and increases linearly with increasing mean free path, to about 10.5% at 4 K. The increase in resitivity Delta rho turns out to be weakly temperature dependent.

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Título según WOS: Surface roughness and size effects of thin gold films on mica
Título según SCOPUS: Surface roughness and size effects of thin gold films on mica
Título de la Revista: PHYSICAL REVIEW B
Volumen: 61
Número: 7
Editorial: American Physical Society
Fecha de publicación: 2000
Página de inicio: 4514
Página final: 4517
Idioma: English