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Detection of lattice strain is crucial for various studies in a nanometer scale because it largely modifies the local electronic states and thus various physical and chemical properties. Here, we demonstrate that the Kondo effect in a single magnetic atom on a metal surface can be a quantum sensor for the local lattice strain. Using low-temperature scanning tunneling spectroscopy, we measured the Kondo resonance in a Co adatom on partially N-adsorbed Cu(001) surfaces, which consist of nanoislands of the Cu 2N monolayer and the clean Cu(001) surface compressed by the surrounding Cu 2N nanoislands. The observed Kondo temperature at the compressed clean surface depends on the area size of the surface, i . e ., the strength of the local lattice strain. This behavior is attributed to the change in the distance between the Co adatom and Cu surface due to the surface lattice strain, which is supported by our density functional calculations. These results provide a way to detect the local strain on the sub-angstrom scale by using the sensitivity of quantum many-body effects.

We demonstrated the fabrication of a rare-earth-free ferromagnetic L10-type Fe–Ni alloy (L10-FeNi) by pulsed laser deposition (PLD). We deposited Fe and Ni on Cu(001) by alternating monoatomic deposition via automatically stabilized laser ablation. We examined the structural properties, magnetic properties, and surface morphology of the alloy specimens as the growth temperature (Ts) was varied. We adequately confirmed the construction of the most prominent L10-FeNi phase at 300 °C, which is significantly higher than previously reported growth temperatures, indicating that PLD followed by thermal treatment promoted two-dimensional growth of the adsorbent. The formation process of L10-FeNi was investigated from the standpoint of surface thermodynamics, and the results suggest that the surface free energy of PLD and its highly instantaneous deposition process by PLD played key roles. Our findings are expected to lead to advanced methods for the fabrication of L10-FeNi.

An epitaxial silicon-oxide monolayer of chemical composition of Si2O3 (the Si2O3 layer) formed on hexagonal SiC(0001¯) surfaces has been observed by scanning tunneling microscopy (STM). Filled- and empty-state STM images with atomic resolution support the previously reported model. Typical structural defects in the Si2O3 layer are found to be missing SiOn (n = 1, 2, 3) molecules. The band gap of the Si2O3 layer obtained by point tunneling spectroscopy is 5.5±0.5 eV, exhibiting considerable narrowing from that of bulk SiO2, 8.9 eV. It is proposed that the Si2O3 layer is suitable as a relevant interface material for formation of SiC-based metal-oxide-semiconductor devices.