2016/06/21 by Davie Mtsuko, Mtsuko, Davie, Christopher Coleman +3
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Diamond and Carbon-based Materials Research #FOS: Physical sciences #High-pressure geophysics and materials #Physics of Superconductivity and Magnetism #Superconductivity (cond-mat.supr-con)
paper · pdf · doi:10.48550/arxiv.1606.06672
openalex publication_date 2016/06/21 · openalex created_date 2017/11/10 · openalex updated_date 2026/07/28
We report on transport features in heavily boron doped nanocrystalline diamond (BNCD) films which are not seen in conventional (s-wave) granular superconductors. Observations include an anomalous resistance peak near to the superconducting transition temperature as well as a strong zero bias conductance peak in the current-voltage spectra. The effect of finite bias current on the evolution of the resistance peak is systematically investigated in this system. The shape of the resistance-temperature curves near the critical temperature is seen to be strongly influenced by both magnetic field and bias current. As the bias current is lowered the resistance peak becomes more pronounced whereas when the magnetic field is varied the peak shifts towards lower temperatures, the resistance upturn shows a quadratic temperature dependence as expected for a Kondo transition. We find that a number of transport features such as resistance peak height, zero bias conduction peak height and width as well as magnetoresistance peaks scale according to a power law dependence. We interpret these features as a result of a charge-Kondo effect where hole dopants act as degenerate Kondo impurities by opening additional pseudo-spin scattering channels.