Activation Energy Distribution of Dynamical Structural Defects in RuO₂ Films
Sheng-Shiuan Yeh1,2*, Tsung-Lin Wu1, Ta-Kang Su1, Juhn-Jong Lin1,2,3
1Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan
2Center for Emergent Functional Matter Science, National Chiao Tung University, Hsinchu, Taiwan
3Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan
* Presenter:Sheng-Shiuan Yeh,
In this study, we demonstrate in a series of sputtered RuO₂ polycrystalline films that the 1/f noise originates from fluctuating oxygen vacancies which act as dynamical structural defects. Reducing the amount of oxygen vacancies by adjusting thermal annealing conditions significantly reduces the noise magnitude γ, the Hooge parameter. We quantify the activation energy distribution function, g(E), and calculate the oxygen vacancy density, nTLS, from the measured γ value. We show that g(E) can be explicitly expressed in terms of γ(T) and the electronic parameters of the metal, where T denotes temperature. The inferred nTLS value is in line with the oxygen content determined from the x-ray photoelectron spectroscopy studies. Our method can be applied to determine the g(E) in a wide variety of small metallic devices.

Keywords: RuO₂ Nanowires, Oxygen Vacancies, Two-level Systems, 1/f noise, Activation Energy Distribution