Determination of electronic band structure of quaternary ferromagnetic Ga0.97-yMn0.03CryAs epitaxial layers

Dönmez Ö., Gunes M., Henini M., Erol A.

PHYSICA B-CONDENSED MATTER, cilt.665, 2023 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 665
  • Basım Tarihi: 2023
  • Doi Numarası: 10.1016/j.physb.2023.415074
  • Dergi Adı: PHYSICA B-CONDENSED MATTER
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Chemical Abstracts Core, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Band anti-crossing model, GaMnCrAs, Magnetic semiconductor, Photoreflectance
  • İstanbul Üniversitesi Adresli: Evet

Özet

Introducing transition metals to conventional III-V semiconductors anomalously changes their fundamental characteristics, such as electronic, magnetic, and structural properties. In this study, we show that the valence band anti-crossing (VBAC) model can be exploited to calculate the electronic band structure of the quaternary Ga0.97-xMn0.03CrxAs epitaxial layers. In this model, the localized Mn and Cr defect states interact with the valence band states (VB), reconstructing VBs and splitting each VB state. The splitting top of the VB state forms an impurity band (IB) and fundamental VB edge. Photomodulated reflectance (PR) spectroscopy is exploited to determine optical transition energies at room temperature. PR spectra were analyzed with the third derivative functional form (TDFF) signal's line shape. The experimental optical transition energies, including band-to-band and spin split-off band transitions, match the calculated optical transition energies by the VBAC model. In the calculation, the interaction energy between localized Mn/Cr-energy level and valence band edges is experi-mentally determined as 0.7 eV.