Multi-conditioned controlled growth of CoBi nanostructures on SrTiO₃

Abstract

Cobalt pnictides have been theoretically proposed to be attractive candidates for high-temperature superconductors. Additionally, monolayered CoX (X = As, Sb, Bi) on SrTiO₃ systems present a potential new platform for realizing topological superconductors in the two-dimensional limit, due to their nontrivial band topology. To this end, we have successfully fabricated high-quality CoBi nanoislands on SrTiO₃ (001) substrates by molecular beam epitaxy followed by an investigation of their atomic structure and electronic properties via in situ scanning tunneling microscopy/spectroscopy. Beyond the previously predicted lattice with a = b = 3.5 Å, 2 × 1 dimer row was observed in this study. Furthermore, our results reveal that the topography of CoBi islands is strongly influenced by various growth conditions, such as substrate temperature, the flux ratio between Co and Bi, and the annealing process. This study paves the way for further explorations of the superconductivity and topological properties of cobalt pnictide systems.

Graphical abstract

Keywords

CoBi/SrTiO₃ / molecular beam epitaxy / scanning tunneling microscopy / scanning tunneling spectroscopy / nanostructure

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Declarations

The authors declare that they have no competing interests and there are no conflicts.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (Nos. 12374196, 92165201, and 11634011), the Innovation Program for Quantum Science and Technology (No. 2021ZD0302800), the CAS Project for Young Scientists in Basic Research (Grant No. YSBR-046), the Fundamental Research Funds for the Central Universities (Grant Nos. WK3510000006 and WK3430000003), and Anhui Initiative in Quantum Information Technologies (No. AHY170000).

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