String Tension and Stability of Magic Tip-Suspended Nanowires
E. Tosatti,123*
S. Prestipino,12
S. Kostlmeier,12
A. Dal Corso,12
F. D. Di
Tolla12
Multishell helical gold nanowires were recently imaged by electron
microscopy. We show theoretically that the contact with the gold tips
at either end of the wire plays a crucial role and that local minima in
the string tension rather than the total wire free energy determine the
nanowire stability. Density functional electronic structure
calculations of the simplest and thinnest coaxial gold and silver wires
of variable radius and chirality were carried out. We found a string
tension minimum for a single-tube gold nanowire that is chiral and
consists of seven strands, in striking agreement with observation. In
contrast, no such minimum was found for silver, where the s-d
competition leading to surface reconstruction is lacking.
1 International School for Advanced Studies
(SISSA);
2 Istituto Nazionale di Fisica della
Materia, Unità SISSA;
3 International Centre
for Theoretical Physics, 34014 Trieste, Italy.
*
To whom correspondence should be addressed. E-mail:
tosatti{at}sissa.it
