Dresden 2026 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

O: Fachverband Oberflächenphysik

O 48: Metal & Semiconductor substrates: Structure, epitaxy and growth

O 48.1: Talk

Tuesday, March 10, 2026, 14:30–14:45, HSZ/0204

Electric-field induced formation of a two-dimensional adatom gas on cryogenic Li(110) — Shyam Katnagallu¹, Samuel Mattoso¹, Huan Zhao^1,2, Se-Ho Kim^1,3, Jing Yang¹, Baptiste Gault^1,4, •Christoph Freysoldt¹, and Jörg Neugebauer¹ — ¹MPI for Sustainable Materials, Düsseldorf Germany — ²State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, China — ³Department of Materials Science and Engineering, Korea University, Seoul, Korea — ⁴Department of Materials, Royal School of Mines, Imperial College London, UK

The field evaporation behavior of Li at 60 K in atom probe tomography (APT) shows very inhomogeneous distribution on the detector hit map with hot-spot sites accounting for thousands of evaporations, implying an unusual high surface mobility. We therefore investigated the ad-atom energetics and diffusion behavior on the prototypical Li(110) surface in the presence of the very high fields (10¹⁰ V/m) by density-functional theory. Two key effects are found to jointly explain the experimentally observed behavior. Firstly, free ad-atoms become energetically favorable over kink sites at fields above 10 V/nm, making sizeable ad-atom densities in thermodynamic equilibrium. Secondly, the ad-atom diffusion barrier vanishes at ∼11 V/nm due to a degeneracy of the on-top and bridge sites. We suggest that a highly dynamic ad-atom gas forms, that enables efficient transport to evaporation hotspot sites. Our static calculations are corroborated by molecular dynamics simulations, that show the spontaneous ad-atom emission from a kink-site enabled by the field.

Keywords: atom probe tomography; ad-atom gas; surface diffusion