Iwao Matsuda

2D anisotropic Dirac cones are observed in χ₃ borophene, a monolayer boron sheet, using high-resolution angle-resolved photoemission spectroscopy. The Dirac cones are centered at the X and X' points. The data also reveal that the hybridization between borophene and Ag(111) is very weak, which explains the preservation of the Dirac cones. As χ₃ borophene has been predicated to be a superconductor, the results may stimulate further research interest in the novel physics of bo

We have succeeded in measuring the resistance across a single atomic step through a monatomic-layer metal on a crystal surface, Si(111)(sqrt[3]xsqrt[3])-Ag, using three independent methods, which yielded consistent values of the resistance. Two of the methods were direct measurements with monolithic microscopic four-point probes and four-tip scanning tunneling microscope probes. The third method was the analysis of electron standing waves near step edges, combined with the Landauer formula for 2

In-plane dispersion of the quantum-well states (QWS's) associated with the electron confinement in metastable epitaxial Ag films grown on the $\mathrm{Si}(111)7\ifmmode\times\else\texttimes\fi{}7$ and $\mathrm{Si}(001)2\ifmmode\times\else\texttimes\fi{}1$ surfaces is investigated by angle-resolved photoemission using synchrotron radiation. In contrast to the free-electron-like behavior expected, these QWS's show intriguing dispersions such as (i) a significant enhancement of the in-plane effecti

Our photoemission spectroscopy results clearly demonstrate that symmetry breakdown in atomic arrangement brings about a lift of degeneracy in electronic states, leading to settle a long-standing controversy on a surface superstructure. We provide unambiguous evidences that $\mathrm{Si}(111)\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3}\ensuremath{-}\mathrm{Ag}$ has the inequivalent triangle structure (IET), excluding a long-lived honeycomb-chained triangle model. We also give critical experi