Masaki Nakano
Bottom-up molecular-beam epitaxy (MBE) provides a complementary approach to top-down mechanical exfoliation in 2D materials research. A great success lies in the application of MBE-grown large-area monolayer films to ARPES and STM/STS studies, unveiling emergent monolayer properties of various 2D materials. Considering the research history of semiconductors and oxides, however, one of the biggest advantages of MBE-based approach should be to create novel material systems unachievable by bulk-based approach and examine their transport phenomena, although such examples are very much limited presumably due to difficulties in making high-enough quality samples.
We have recently developed a fundamental route to layer-by-layer epitaxial growth of a wide variety of 2D materials and their heterostructures on insulating substrates by MBE [1-7], opening a door for exploration of emergent transport phenomena of 2D materials arising at the monolayer limit and at the interface between dissimilar materials even based on hardly-cleavable, chemically-unstable, and/or thermodynamically-metastable compounds. In this presentation, I will introduce our recent achievements in particular on the MBE-grown 2D magnets and their heterostructures, including observation of the emergent itinerant 2D ferromagnetism with intrinsic spin polarization in hardly-cleavable compound that are missing in its bulk counterpart [4], as well as control of its magnetic properties by the magnetic proximity effect across the van der Waals interface [7].
Reference:
[1] M. Nakano et al., Nano Lett. 17, 5595 (2017). [2] Y. Wang et al., Appl. Phys. Lett. 113, 073101 (2018). [3] Y. Kashiwabara et al., Adv. Funct. Mater. 29, 1900354 (2019). [4] M. Nakano et al., Nano Lett. 19, 8806 (2019). [5] Y. Tanaka et al., Nano Lett. 20, 1725 (2020). [6] H. Matsuoka et al., Rhys. Rev. Research 2, 012064(R) (2020). [7] H. Matsuoka et al., submitted.