Issue 43, 2016

Impurity effects on solid–solid transitions in atomic clusters

Abstract

We use the harmonic superposition approach to examine how a single atom substitution affects low-temperature anomalies in the vibrational heat capacity (CV) of model nanoclusters. Each anomaly is linked to competing solidlike “phases”, where crossover of the corresponding free energies defines a solid–solid transition temperature (Ts). For selected Lennard-Jones clusters we show that Ts and the corresponding CV peak can be tuned over a wide range by varying the relative atomic size and binding strength of the impurity, but excessive atom-size mismatch can destroy a transition and may produce another. In some tunable cases we find up to two additional CV peaks emerging below Ts, signalling one- or two-step delocalisation of the impurity within the ground-state geometry. Results for Ni74X and Au54X clusters (X = Au, Ag, Al, Cu, Ni, Pd, Pt, Pb), modelled by the many-body Gupta potential, further corroborate the possibility of tuning, engineering, and suppressing finite-system analogues of a solid–solid transition in nanoalloys.

Graphical abstract: Impurity effects on solid–solid transitions in atomic clusters

Supplementary files

Article information

Article type
Paper
Submitted
08 8 2016
Accepted
08 10 2016
First published
10 10 2016
This article is Open Access
Creative Commons BY license

Nanoscale, 2016,8, 18326-18340

Impurity effects on solid–solid transitions in atomic clusters

B. E. Husic, D. Schebarchov and D. J. Wales, Nanoscale, 2016, 8, 18326 DOI: 10.1039/C6NR06299G

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