Hybrid MBE Growth of Epitaxial, Single Crystalline Pt Films

The growth of single-crystalline, epitaxial platinum (Pt) films has been of significant interest as a chemically and thermally stable electrode material, owing to their high work function (~5.5 eV) and excellent lattice matching (3.924 Å) with many functional perovskite oxides. However, obtaining high-quality Pt (001) films with atomically smooth surfaces remains challenging, particularly because stabilizing the (001) orientation is difficult – Pt thermodynamically favors the formation of low-energy (111) facets. In this work, we demonstrate the hybrid MBE growth of metallic, epitaxial, single-crystalline Pt (001) films using the metal-organic precursor Pt(acac)₂. Subsequent growth of epitaxial SrTiO₃ on these Pt (001) layers yields single-crystalline SrTiO₃ films exhibiting atomically terraced surfaces and bulk-like dielectric constants, and extremely low leakage. We discuss the synthesis, structure, and morphology-property relationships of both Pt (001) and Pt/SrTiO₃ (001) heterostructures. This work establishes hybrid MBE as a robust and versatile approach for realizing high-quality Pt films and, more broadly, for extending epitaxial synthesis to other platinum-group metals.