Finite-temperature structures of Cu, Ag, and Au nanoclusters Manoj Settem 1 , Riccardo Ferrando 2 and Alberto Giacomello 1 1 Sapienza Università di Roma, Dipartimento di Ingegneria Meccanica e Aerospaziale, Italy, 2 Università di Genova, Dipartimento di Fisica, Via Dodecaneso 33, Italy manoj.settem@uniroma1.it In this work we study the equilibrium structures of small metal nanoclusters (1 to 2 nm) in the whole temperature range from 0 K to melting. Our approach relies on combining the accuracy of Harmonic Superposition Approximation (HSA) at low temperatures and Parallel Tempering Molecular Dynamics (PTMD) at high temperatures [1]. This combined methodology is applied to Cu, Ag, and Au nanoclusters to reveal the size- and temperature-dependent competition between the global energy minimum and other structural motifs (Fig. 1 shows the equilibrium structures of Cu 90 , Ag 90 , and Au 90 clusters). Typically, the global energy minimum remains the dominant motif at finite temperatures as well. However, in other cases, the global minimum undergoes a solid- solid transformation either completely to a different motif or competes with other motifs. Finally, the metal specific differences will be presented; for instance, Cu clusters show a strong preference for icosahedra while Au disfavors icosahedra.
Figure 1 : Occurrence fraction of various structural motifs of Cu 90 , Ag 90 , and Au 90 as a function of temperature obtained via PTMD simulations. References 1. Settem, M., Ferrando, R., & Giacomello, A. (2022). Tempering of Au nanoclusters: capturing the temperature-dependent competition among structural motifs. Nanoscale , 14 (3), 939-952.
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© The Author(s), 2022
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