Break conductance of Al nanocontacts

We measured a break conductance, the last conductance of a contact before its complete break, for Al nanocontacts of 0–200G0(G0≡2e2/h is the quantum unit of conductance) in ultrahigh vacuum at room temperature. We found that the distribution of the break conductance shows a broad single peak, the position of which shifts with the contact current. From the observed current dependence of the break conductance peak, it is suggested that Al nanocontacts break up most likely when the contact current density reaches a critical value ∼5×1010 A/cm2.