Controlling magnetic order, magnetic anisotropy, and band topology in the semimetals Sr(Mn_0.9Cu_0.1)Sb₂ and Sr(Mn_0.9Zn_0.1)Sb₂

Journal Article · Fri Aug 14 00:00:00 EDT 2020 · Physical Review B

DOI:https://doi.org/10.1103/physrevb.102.085130· OSTI ID:1657119

Islam, Farhan ^[1]; Choudhary, Renu  ^[1]; Liu, Yong  ^[2]; Ueland, Benjamin G.  ^[1]; Paudyal, Durga  ^[1]; Heitmann, Thomas ^[3]; McQueeney, Robert J. ^[1]; Vaknin, David  ^[1]

---

1. Ames Lab., and Iowa State Univ., Ames, IA (United States)
2. Ames Lab., and Iowa State Univ., Ames, IA (United States); Ecole Polytechnique Federale Lausanne (Switzlerland)
3. Univ. of Missouri, Columbia, MO (United States)

Neutron diffraction and magnetic susceptibility studies show that orthorhombic single-crystals of topological semimetals Sr(Mn_0.9Cu_0.1) Sb₂ and Sr(Mn_0.9Zn_0.1)Sb₂ undergo three-dimensional C-type antiferromagnetic (AFM) ordering of the Mn²⁺ moments at T_N = 200 ± 10 and 210 ± 12 K, respectively, significantly lower than that of the parent SrMnSb₂ with T_N = 297 ± 3 K. Magnetization versus applied magnetic field (perpendicular to MnSb planes) below T_N exhibits slightly modified de Haas van Alphen oscillations for the Zn-doped crystal as compared to that of the parent compound. By contrast, the Cu-doped system does not show de Haas van Alphen magnetic oscillations, suggesting that either Cu substitution for Mn changes the electronic structure of the parent compound substantially, or that the Cu sites are strong scatterers of carriers that significantly shorten their mean free path thus diminishing the oscillations. Density functional theory (DFT) calculations including spin-orbit coupling predict the C-type AFM state for the parent, Cu-, and Zn-doped systems and identify the a -axis (i.e., perpendicular to the Mn layer) as the easy magnetization direction in the parent and 12.5% of Cu or Zn substitutions. In contrast, 25% of Cu content changes the easy magnetization to the b-axis (i.e., within the Mn layer). Here, we find that the incorporation of Cu and Zn in SrMnSb₂ tunes electronic bands near the Fermi level resulting in different band topology and semimetallicity. The parent and Zn-doped systems have coexistence of electron and hole pockets with opened Dirac cone around the Y-point whereas the Cu-doped system has dominant hole pockets around the Fermi level with a distorted Dirac cone. The tunable electronic structure may point out possibilities of rationalizing the experimentally observed de Haas van Alphen magnetic oscillations.

• Research Organization: Ames Lab., Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division; USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing Office
• Grant/Contract Number: AC02-07CH11358
• OSTI ID: 1657119
• Report Number(s): IS-J-10,297; TRN: US2203226
• Journal Information: Physical Review B, Vol. 102, Issue 8; ISSN 2469-9950
• Publisher: American Physical Society (APS)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY