Materials Functionality Design

Group Web Site

[ Professor ] Masafumi Shirai
Materials Functionality Design

[ Associate Professor ] Kazutaka Abe
Materials Science under Extreme Conditions

[ Assistant Professor ] Masato Tsujikawa

[ Assistant Professor ] Hikari Shinya

[ Research Fellow ] Tufan Roy

[ Research Fellow ] Jun-ichiro Inoue

Research Activities

Various kinds of materials are utilized for processing, communication, and storage of massive data in modern information devices. Our research objectives are as follows: (1) theoretical analyses of quantum phenomena in materials and nanostructures, (2) computational design of materials and nanostructures which possess new functionalities, (3) development of materials design scheme utilizing large-scale computational simulation techniques.

Materials Functionality Design (Prof. Shirai)

Our research interest is focused on “spintronics” to realize new functional devices. The main topic is theoretical analysis of spin-dependent transport properties in highly spin-polarized materials. We extend our theoretical research to electric-field effect on magnetic anisotropy in ferromagnetic films for realizing low power-consumption devices.
We reveal the origin of voltage controlled magnetic anisotropy (VCMA) at the MgO/Pt/Fe interface by ab initio calculations and XMCD measurements. The voltage-induced electric quadrupole of Pt atom contributes to VCMA.
To realize semiconductor spintronics materials with novel functionalities, we propose new methods for controlling the magnetic properties and demonstrate materials design of ferromagnetic semiconductors (FMSs), on the basis of the first-principles calculations and model simulations. We also develop first-principles approaches to estimate the transport properties at finite temperature for half-metallic materials and spin-gapless semiconductors.

Research topics

  • Design of new spintronics materials based on first-principles calculation and machine learning
  • Theoretical analysis of transport properties in spintronics devices
  • Computational simulation of nanostructuregrowth process on surface
  • Development of simulation scheme for material/device functionality design
Fig.1: Voltage-induced modulation of charge distribution of Pt atom at the MgO/Pt/Fe interface

Materials Science under Extreme Conditions(Assoc. Prof. Abe)

We intend to contribute future information and communication technology through the development of novel nano-scale dielectric measurement systems for the evaluation of the emerging electronic materials and devices. In particular, we are developing a new scanning probe potentiometry method called scanning nonlinear dielectric potentiometry for the atomic-scale quantitative investigation of material properties regarding electric polarization on surfaces and interfaces. By integrating the new method with the existing microscopy methods, we are also working on the establishment of a multifunctional scanning probe microscopy system towards the advanced analysis and characterization of the next-generation materials and devices including two-dimensional crystals (Fig.3).

Research topics

  • Matter at high densities.
  • Metallization and superconductivity of hydrogen and hydrides.
  • Development of first-principles structural search methods
Fig.2: The “Dairiseki” phase (left) and the “Konbu” phase (right) as a consequence of spinodal nano-decomposition in (In,Fe)Sb FMS