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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 CoS₂is 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 thek_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 thed‐wave‐like spin‐orbit coupling among spin‐polarizede_g orbitals.

The study of the high critical temperature (T_c) of hydrogen compounds under high pressure has resulted in a considerable focus on Bardeen–Cooper–Schrieffer superconductors. Nb has the highestT_camong the elemental metals at ambient pressure, so reviewing Nb films again is worthwhile. In this study, we investigated the factors that determine theT_cof Nb films by strain introduction and carrier doping. We deposited Nb films of various thicknesses onto Si substrates and evaluated theT_cvariation with thickness. In-plane compressive strain in the (110) plane due to residual stress reduced theT_c. First-principles calculations showed that adjusting the density of states at the Fermi level is key for both strain-induced suppression and doping-induced enhancement of the NbT_c. The application of hydrostatic pressure compensated for the intrinsic strain of the film and increased itsT_c, which could also be enhanced by increasing the hole concentration with an electric double-layer transistor. A liquid electrolyte should be used as a pressure medium for applying hydrostatic pressure to increase theT_cof correlated materials, where this increase results from changes in material structure and carrier concentration.