1/f noise in single-crystalline RuO2 nanowires
Sheng-Shiuan Yeh1*, An-Shao Lien1, Wen-Yao Chang1, Juhn-Jong Lin1,2
1Institute of Physics, National Chiao Tung University, Hsinchu, Taiwan
2Department of Electrophysics, National Chiao Tung University, Hsinchu, Taiwan
* presenting author:Sheng-Shiuan Yeh, email:yehshengshiuan@gmail.com
We have measured the low frequency resistance fluctuations of individual single-crystalline RuO2 nanowires with diameters of ~50 to ~200 nm at low temperatures. The ac techniques were employed to the fluctuation measurement, which minimized the contribution from noise of the preamplifier, and thus the intrinsic noise of our RuO2 nanowires could be obtained. We observed pronounced resistance fluctuations with 1/f power spectrum density (PSD), which indicates the existence of large amounts of dynamic two-level systems (TLSs) in our RuO2 nanowires. In particular, the Kondo-like behavior of ρ(T) has also been observed, where ρ denotes the average resistivity. The ρ(T) dependence in all T regimes can be well described by the numerical renormalized group (NRG) calculation for the Kondo effect. We ascribe the observed Kondo effect to be induced by the interaction of conduction electrons and dynamic TLSs in our RuO2 nanowires.

Keywords: 1/f noise, two-level system, Kondo effect, nanowire, RuO2