Study of electronic and spin structure in B20-type 3d transition metal monosilicide

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K03519
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13030:Magnetism, superconductivity and strongly correlated systems-related
• Research Institution: Hiroshima University
• Principal Investigator: Arita Masashi 広島大学, 技術センター, 技術専門職員 (20379910)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: スピン・角度分解光電子分光 / 近藤半導体 / 強相関物質

Outline of Final Research Achievements

FeSi has been studied for many years because the magnetic and electric properties are similar to those of the 4f Kondo insulators. Recently, FeSi and other transition metal monosilicides, which have a non-centrosymmetric structure, have attracted many researchers for the existence of the new surface states and unusual spin texture. In order to investigate the electron correlation effect and the spin texture in FeSi, the angle-resolved photoemission spectroscopy (ARPES) measurements on mechanically polished FeSi surfaces were carried out. We succeeded in obtaining the clear ARPES images along G -X and X-M lines and estimating the intensity of the electron-electron interaction with the whole band structure. By spin-resolved ARPES, the spin component perpendicular to the G-X-M-X plane could be found out near the Fermi energy along G -X. Though the spin polarization is very weak, the spin polarizations are reversed between opposite k points with respect to G point (k=0).

Free Research Field

固体物性

Academic Significance and Societal Importance of the Research Achievements

FeSiは、ありふれた元素の化合物であるが、3d電子系における近藤絶縁体として強い電子相関効果に対する研究が長年なされている。近年では、トポロジカル近藤半導体SmB6や同様の空間反転対称性が破れた結晶構造を持つCoSiなどの類似物質としても注目されている。結晶構造は構造は空間反転対称性の破れを持ち、スピン軌道相互作用（SOI）を顕在化させると考えられる。
今回の成果のうち、電子相関効果の研究は、金属絶縁体転移や特異な温度による磁化率の変化の解明につながる。またバルクでの特異なスピン構造は、比較的軽元素である3d遷移金属化合物でも、系の対称性によりSOI効果が顕著になっている証拠である。