Evidence of quantum phase slip effect in titanium nanowires

Electron transport properties of titanium nanowires were experimentally studied. Below the effective diameter 50 nm all samples demonstrated a pronounced broadening of the $R(T)$ dependencies, which cannot be accounted for by thermal fluctuations. Extensive microscopic and elemental analyses indicate the absence of structural or/and geometrical imperfections capable of broadening the $R(T)$ transition to such an extent. We associate the effect with quantum fluctuations of the order parameter.