Evidence of quantum phase slip effect in titanium nanowires
  Electron transport properties of titanium nanowires were experimentally studied. Below the effective diameter $\lesssim$ 50 nm all samples demonstrated a pronounced broadening of the $R(T)$ dependencies, which cannot be accounted for thermal flcutuations. An extensive microscopic and elemental analysis indicates the absence of structural or/and geometrical imperfection capable to broaden the the $R(T)$ transition to such an extent. We associate the effect with quantum flucutuations of the order parameter. 
Janne Lehtinen, Timo Sajavaara, Konstantin Arutyunov, Alexander   Vasiliev
cond-mat.supr-con cond-mat.mes-hall