Nanowire formation at metal-metal contacts

The thinnest nanocontacts between two metal bodies take sometimes the shape of regular ultra-thin suspended nanowires. I will qualitatively review here some of the theory work done in our group in connection with this phenomenon. I will discuss why nanowires arise, their stability, and their evolution with time. I will touch on the formation mechanism of 'magic' long lived nanowires endowed with especially stable structures, on their spontaneous thinning, and on the helical and the monatomic magic nanowires observed mostly in gold.