Tunable Colossal Anomalous Hall Conductivity in Half-Metallic Material Induced by d-Wave-Like Spin-Orbit Gap

Joonyoung Choi; Jin-Hong Park; Wonshik Kyung; Younsik Kim; Mi Kyung Kim; Junyoung Kwon; Changyoung Kim; Jun-Won Rhim; Se Young Park; Younjung Jo

doi:10.1002/advs.202307288

Tunable Colossal Anomalous Hall Conductivity in Half-Metallic Material Induced by d-Wave-Like Spin-Orbit Gap

Adv Sci (Weinh). 2024 May;11(20):e2307288. doi: 10.1002/advs.202307288. Epub 2024 Mar 21.

Authors

Joonyoung Choi¹, Jin-Hong Park², Wonshik Kyung^{3

4}, Younsik Kim^{3

4}, Mi Kyung Kim⁵, Junyoung Kwon⁶, Changyoung Kim^{3

4}, Jun-Won Rhim^{2

7}, Se Young Park^{8

9}, Younjung Jo¹

Affiliations

¹ Department of Physics, Kyungpook National University, Daegu, 41566, South Korea.
² Research Center for Novel Epitaxial Quantum Architectures, Department of Physics, Seoul National University, Seoul, 08826, South Korea.
³ Center for Correlated Electron Systems, Institute for Basic Science, Seoul, 08826, South Korea.
⁴ Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
⁵ Department of Physics, Yonsei University, Seoul, 03722, South Korea.
⁶ Department of Physics, Pohang University of Science and Technology, Pohang, 37673, South Korea.
⁷ Department of Physics, Ajou University, Suwon, 16499, South Korea.
⁸ Department of Physics and Origin of Matter and Evolution of Galaxies (OMEG) Institute, Soongsil University, Seoul, 06978, South Korea.
⁹ Integrative Institute of Basic Sciences, Soongsil University, Seoul, 06978, South Korea.

Abstract

The anomalous Hall conductivity (AHC) in magnetic materials, resulting from inverted band topology, has emerged as a key adjustable function in spin-torque devices and advanced magnetic sensors. Among systems with near-half-metallicity and broken time-reversal symmetry, cobalt disulfide (CoS₂) has proven to be a material capable of significantly enhancing its AHC. In this study, the AHC of CoS₂ is empirically assessed by manipulating the chemical potential through Fe- (hole) and Ni- (electron) doping. The primary mechanism underlying the colossal AHC is identified through the application of density functional theory and tight-binding analyses. The main source of this substantial AHC is traced to four spin-polarized massive Dirac dispersions in the k_z = 0 plane of the Brillouin zone, located slightly below the Fermi level. In Co_0.95Fe_0.05S₂, the AHC, which is directly proportional to the momentum-space integral of the Berry curvature (BC), reached a record-breaking value of 2507 Ω^-1cm^-1. This is because the BCs of the four Dirac dispersions all exhibit the same sign, a consequence of the d-wave-like spin-orbit coupling among spin-polarized e_g orbitals.

Keywords: anomalous hall effect; berry curvature; half‐metals.

Abstract

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