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arXiv · 2610.27428

In Situ Thermal Preparation by CO$_2$-Laser and Chemical Characterization of Oxide Substrates Across Multiple Crystallographic Orientations

Neethu Rose Leyo·Sethulakshmi Sajeev·Arnaud P. Nono Tchiomo·Prosper Ngabonziza
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Abstract

Atomically flat and chemically controlled oxide substrate surfaces are essential for high-quality epitaxial growth of complex materials and heterostructures. Previous studies have demonstrated in situ thermal preparation of selected oxide substrates, primarily focusing on conventional low-index orientations such as SrTiO$_3$ (100) and LaAlO$_3$ (100). Here, we extend these methodologies to a broader range of oxide substrates and crystallographic orientations, including challenging polar surfaces. We present a systematic study of the in situ thermal preparation of SrTiO$_3$ (100), SrTiO$_3$ (111), GdScO$_3$ (110), LaAlO$_3$ (111), (LaAlO$_3$)$_{0.3}$(Sr$_2$AlTaO$_6$)$_{0.7}$ (001), and NdGaO$_3$ (110) single crystal substrates. The substrates are annealed in a vacuum chamber under a controlled oxygen background environment using a CO$_2$ laser heating system. The optimized annealing conditions produce atomically flat step-and-terrace structures, long-range surface crystallinity, and effectively clean surfaces across all the investigated substrates. Our results establish a versatile, reproducible, and broadly applicable platform for the in situ preparation of oxide substrates immediately prior to epitaxial growth. These results also provide practical guidelines for interface engineering and surface-sensitive investigations of complex materials.

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Neethu Rose Leyo, Sethulakshmi Sajeev, Arnaud P. Nono Tchiomo, Prosper Ngabonziza. 2026-10-20. In Situ Thermal Preparation by CO$_2$-Laser and Chemical Characterization of Oxide Substrates Across Multiple Crystallographic Orientations. https://arxiv.org/abs/2610.27428

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