Takeshi Nakagawa

Due to its unique electronic properties, boron tends to form various multicenter bonds, enabling the construction of diverse two-dimensional borophene structures through modulation of the number and distribution of boron vacancies within a triangular lattice. In this study, we investigate a large-hole borophene model on heated Ni(111) substrates via molecular beam epitaxy under ultra-high-vacuum conditions. The complex atomic arrangement and electronic structures were investigated by scanning tunneling microscopy, low-energy electron diffraction, angle-resolved photoemission spectroscopy, and density functional theory calculations. Our results suggest that boron atoms are initially incorporated into the Ni surface and preferentially nucleated at step edges. The favorable geometric matching between the proposed structure and the Ni step-edge configuration contributes to the stabilization of the structure and facilitates its formation under the present growth conditions. These findings broaden the structural diversity of 2D borophene sheets and offer insights into the controlled synthesis of complex borophene architectures on metallic substrates.

The growth of Sn overlayers on the W(110) surface is investigated using low‐energy electron diffraction analysis. The structural investigation reveals Sn adsorption sites on the W(110) for (1 × 3) and (1 × 4) structures. During the formation of the (1 × 3) structure, Sn atoms are only adsorbed on the threefold hollow sites. However, at higher coverages, Sn atoms are adsorbed on the fourfold hollow sites after the threefold hollow sites are filled up to form the (1 × 4) structure, resulting in a dense overlayer structure. Both structures are overlayer with no alloy formation at the interface. The (1 × 3) phase exhibits a temperature‐reversible phase transition below ≈270 K. At low temperatures, a phase with long‐range order is developed.

Magnetic and chemical properties of ultrathin Fe films on molybdenum disulfide (MoS₂) are investigated using magneto‐optic Kerr effect (MOKE) and X‐ray photoemission spectroscopy (XPS). A magnetization hysteresis loop is found after nominal 10 Å of Fe deposition on MoS₂ at room temperature. The thickness‐dependent MOKE measurement evaluates that the magnetic dead layer (MDL) exists up to ≈2 Å of Fe on MoS₂ due to the interaction between Fe and MoS₂. XPS shows small peak shifting for Mo 3d and S 2p peaks toward lower binding energies with initial Fe deposition, indicating the modification of surface band bending. Fe 2p peaks for lower thickness of Fe are significantly broader than those for higher thickness, which is attributed to the coexistence of metallic and ionic Fe in the film. The presence of ionic Fe, localized at the interface, indicates strong interactions between Fe and MoS₂, and the existence of chemical bonding at the interface is corroborated with the formation of MDL.