delta layer

https://doi.org/10.1351/goldbook.09243
Layer of discrete composition, one atom thick, formed during the growth of material on a substrate.
Note: These films are often formed during epitaxial growth on single-crystal substrates.
Source:
PAC, 2020, 92, 1781. (Glossary of methods and terms used in surface chemical analysis (IUPAC Recommendations 2020)) on page 1802 [Terms] [Paper]