Computational design and evaluation of spintronics materials

• Applicant: Dr. Daniel Wortmann
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 2009 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 151226633

• Final Report Year: 2014

Final Report Abstract

Using the computational power provided by modern supercomputers we simulated materials properties and complex junctions. Besides the basic design of such materials and interfaces we evaluated key quantities like the magnetic ordering temperatures to estimate their potential for possible spintronic device concepts. Our focus was here on diluted magnetic impurities in semiconductors and on quasi one-dimensional nanostructures which could be grown by self-organization. Electronic transport through nanojunctions was also studied by density functional theory in combination with linear response theory to identify the relevant bottlenecks and fundamental processes important for spin-polarized transport. As a project with funding only for collaboration and traveling and with no funds for personal a key activity in the project was the organization of visits of the Jülich researchers to Osaka and vice versa. In this context we also organized four mini workshops which took place alternating between Japan and Germany.

Publications

• Ballistic Electron Transport through Atomic Nanowires, Journal of Computational and Theoretical Nanoscience, 6, 2521-2544 (2009)
  S. Tsukamoto, Y. Egami and T. Ono
  
• "First principle theory of dilute magnetic semiconductors", Reviews of Modern Physics, 82, 1633 (2010)
  K. Sato, L. Bergqvist, J. Kudnovský, P. H. Dederichs, O. Eriksson, I. Turek, B. Sanyal, G. Bouzerar, H. Katayama-Yoshida, V. A. Dinh, T. Fukushima, H. Kizaki, R. Zeller
  
• "Real-space electronic-structure calculations with full-potential all-electron precision for transition-metals", Phys. Rev. B 82, 205115 (2010)
  . T. Ono, M. Heide, N. Atodiresei, P. Baumeister, S. Tsukamoto, and S. Blügel
  
• "Computational materials design for high-Tc (Ga, Mn)As by Li codoping", Phys. Rev. B 83, 165201 (2011)
  L. Bergqvist, K. Sato, P. H. Dederichs and H. Katayama-Yoshida
  
• "Interstitial donor co-doping method in (Ga, Mn)As to increase solubility and Curie temperature", Appl. Phys. Express 4, 043003 (2011)
  H. Fujii, K. Sato, L.Bergqvist, P. H. Dederichs and H. Katayama-Yoshida
  
• Design of dilute magnetic semiconductors with room-temperature ferromagnetism by controlling spinodal decomposition, European Materials Research Society Fall meeting (13-17, Sep. 2011, Warsaw, Poland)
  K. Sato, H. Fujii, H. Katayama-Yoshida, L. Bergqvist, P. H. Dederichs, T. Fukushima
  
• First-principles study on atomic configuration of electron-beam irradiated C60 film, Phys. Rev. B 84, 165410 (2011)
  T. Ono and S. Tsukamoto
  
• Materials design of dilute magnetic semiconductors by controlling the spinodal decomposition, International Conference on Core research and Engineering Science of Advanced Materials (31 May - 4 Jun. 2011, Osaka, Japan)
  K. Sato, H. Fujii, L. Bergqvist, P. H. Dederichs, H. Katayama-Yoshida
  
• Real-space calculations for electron transport properties of nanostructures, J. Phys.: Condens. Matter 23 394203, 1 (2011)
  T. Ono, S. Tsukamoto, Y. Egami, and Y. Fujimoto
  
• Stabilized scattering wave-function calculations using the Lippmann-Schwinger equation for long conductor systems, Phys. Rev. B 84, 115443 (2011)
  S. Tsukamoto, Y. Egami, K. Hirose, and S. Blügel
  
• First-principles calculation methods for obtaining scattering waves to investigate transport properties of nanostructures, Quantum Matter 1, 4 (2012)
  T. Ono, Y. Fujimoto, and S.Tsukamoto