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物理工学ユニットでは、以下のように談話会を 対式+遠隔（ハイブリッド）形式で開催させて頂きます。

講演者：Dr. Oksana Yastrubchak
          (V.E. LashkaryovInstitute of Semiconductor Physics, National Academy of Sciences of Ukraine, pr. Nauky41, 03028, Kyiv, Ukraine)
演題：　Band-Structure Engineering in MBE-grown Multicomponent Dilute Semiconductors
日時：　2023年12月12日（火）15：00 - 16：00
場所：　総合研究棟　W202会議室　+　Zoom（ミーティングID：963 6492 4569）
          Zoomのパスコードは、物理工学教員にお問い合わせください。

概要： Dilute magnetic semiconductors (DMSs) represent a class of alloys which combine semiconductor properties with magnetism integrated into a single material. Their magnetic properties arise from transition metal ions introduced into the semiconductor host lattice. The combination of electronic and magnetic properties results in entirely new physical properties that are of interest in basic science and, importantly, hold promise of a wide range of device application referred to as spintronics.
Impact of P, Bi and Mnincorporation into GaAs layers on their electronic-and band-structures as well as magnetic and structural properties has been studied. A set of the homogenous (Ga,Mn)(P,As) and (Ga,Mn)(Bi,As) layers of high structural perfection have been grown by the low-temperature molecular-beam epitaxy technique. Post-growth annealing treatment of the layers results in an improvement of their structural and magnetic properties and an increase in the free hole concentration in the layers. Hard-X-ray angular-resolved photoemission spectroscopy (HARPES) reveals that a strongly dispersing band crosses the Fermi energy in the highly doped samples. This is a consequence of the high concentration of Mn-induced itinerant holes residing in the valence band of the III-V semiconductor host. The spectroscopic ellipsometry (SE) and photo-reflectance spectroscopy results confirmed the modification of the valence band of the epitaxial layers. This study was supported by the micro-Raman and SQUID magnetometrymeasurements.



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世話人：一柳優子