Research area | Mathematics, Physics and Engineering |
Title | Coupled Sublattice Melting and Charge-Order Transition in Two Dimensions |
Publication Type | Journal Article |
Publication year | 2020 |
Authors | Smith, TS, Ming, F, Trabada, DG, Gonzalez, C, Soler-Polo, D, Flores, F, Ortega, J, Weitering, HH |
Journal | Phys. Rev. Lett. |
Volume | 124 |
Pages | 097602 |
Abstract | Two-dimensional melting is one of the most fascinating and poorly understood phase transitions in nature. Theoretical investigations often point to a two-step melting scenario involving unbinding of topological defects at two distinct temperatures. Here, we report on a novel melting transition of a charge-ordered K-Sn alloy monolayer on a silicon substrate. Melting starts with short-range positional fluctuations in the K sublattice while maintaining long-range order, followed by longer-range K diffusion over small domains, and ultimately resulting in a molten sublattice. Concomitantly, the charge order of the Sn host lattice collapses in a multistep process with both displacive and order-disorder transition characteristics. Our combined experimental and theoretical analysis provides a rare insight into the atomistic processes of a multistep melting transition of a two-dimensional materials system. |
DOI | 10.1103/PhysRevLett.124.097602 |