1995/11/01 by Shobhana Narasimhan, Matthias Scheffler, Narasimhan, Shobhana +1
Engineering · Materials Science · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Thermal Expansion and Ionic Conductivity #Thermal properties of materials #Thermodynamic and Structural Properties of Metals and Alloys
paper · pdf · doi:10.48550/arxiv.mtrl-th/9511001
openalex publication_date 1995/11/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We investigate the thermal behavior of the (111) surface of silver, using phonon frequencies obtained from ab initio total energy calculations, and anharmonic effects treated within a quasiharmonic approximation. Our results reproduce the experimental observation of a large and anomalous increase in the surface thermal expansion at high temperatures [P. Statiris et al., Phys. Rev. Lett. 72, 3574 (1994)]. Surprisingly, we find that this increase can be attributed to a rapid softening of the in-plane phonon frequencies, rather than due to the anharmonicity of the out-of-plane surface phonon modes. This provides evidence for a new mechanism for the enhancement of surface anharmonicity. A comparison with Al(111) shows that the two surfaces behave quite differently, with no evidence for such anomalous behavior on Al(111).