Professor Hiroshi Yamagami

Area and Subject Taught Solid-State Electron Theory
Research Theme(s) Theoretical Research on Electronic Structure of Strongly-Correlated f-Electron Systems
Academic Degrees Doctor of Philosophy, Niigata University
Keywords for Research Field Solid-State Physics
Office Phone Number Not Public
e-mail E-mail

Research Overview

Condensed-matters are formed by a combination of over 100 types of atoms, and their physical properties are highly diverse: Progress in materials processing technologies has enabled a creation of any artificial materials with useful characteristics, distinctive to natural materials. According to some physical phenomena, the condensed-matters are classified as metals, semiconductors, insulators, superconductors, magnets and so on, and the underlying "solid-state physics" is the discipline that theoretically derives their phenomena from the fundamental principles of physics. The quantum mechanics for electronic states in solids is called electronic structure theory or "band theory", being regarded as the most basic theory in the solid-state physics. The band theory gives a first principles method to calculate the electronic structure, and clearly explains the general classification of materials based on electric conductivity. Moreover, a current band theory must be developed so as to consider a strongly correlated aspect of the electrons in many-electron system, and there are a lot of research issues that need to overcome, including some extensions of the band theory.
In recent years, the single-crystal growth of heavy-fermion compounds such as uranium or other transuranic compounds is carried out and accordingly anomalous magnetism and novel superconductivity phenomena are observed with these materials. In order to quantitatively clarify the electron structures of these magnetic compounds, we have developed a relativistic band theory based on the spin-density functional method. The goal of our research is to elucidate the Fermi surfaces and magnetic properties from the electron structures by the first principles calculation and to build a model that can systematically explain a variety of the measured results.

Notable Publications and Works in the Last Three Years

  1. Separation of magnetic properties of Uranium and Cobalt sites in UCoAl using soft x-ray magnetic circular dichroism, Phys. Rev. B85 (2014) 075108.
  2. Band structure and Fermi surface of UPd3 studied by soft x-ray angle-resolved photoemission spectroscopy, Phys. Rev. B87(2013) 075142.
  3. Observation of bulk band dispersions of YbRu2Si2 using soft x-ray angle-resolved photoemission spectroscopy Phy. Rev. B87(2013) 075131.
  4. Itinerant nature of U 5f states in uranium nononitride revealed by angle-resolved photoelectron spectroscopy, Phys. Rev. B86(2012) 235108.
  5. Electronic structure of YbCu2Ge2 studeied by angle-resolved photoemission spectroscopy, Phys. Rev. B84(2011) 195121.