We provide a straightforward and efficient procedure to combine the local density approximation plus Hubbard U (LDA+U) total-energy functional with the full-potential linearized augmented plane-wave method. A detailed derivation of the LDA+U Kohn-Sham-type equations is presented for the augmented plane-wave basis set, and a simple “second-variation”-based procedure for self-consistent LDA+U calculations is given. The method is applied to calculate the electronic structure and magnetic properties of NiO and Gd. The magnetic moments and band eigenvalues obtained are in very good quantitative agreement with previous full-potential linear muffin-tin orbital calculations. We point out that LDA+U reduces the total d charge on Ni by 0.1 in NiO.

Magnetic anisotropy phenomena in bimetallic antiferromagnets ${\text{Mn}}_2\text{Au}$ and MnIr are studied by first-principles density-functional theory calculations. We find strong and lattice-parameter-dependent magnetic anisotropies of the ground-state energy, chemical potential, and density of states, and attribute these anisotropies to combined effects of large moment on the $\text{Mn}3d$ shell and large spin-orbit coupling on the $5d$ shell of the noble metal. Large magnitudes of the proposed effects can open a route towards spintronics in compensated antiferromagnets without involving ferromagnetic elements.

Recent studies in devices comprising metal antiferromagnets have demonstrated the feasibility of a novel spintronic concept in which spin-dependent phenomena are governed by an antiferromagnet instead of a ferromagnet. Here we report experimental observation of the anisotropic magnetoresistance in an antiferromagnetic semiconductor Sr₂IrO₄. Based on ab initio calculations, we associate the origin of the phenomenon with large anisotropies in the relativistic electronic structure. The antiferromagnet film is exchange coupled to a ferromagnet, which allows us to reorient the antiferromagnet spin-axis in applied magnetic fields via the exchange spring effect. We demonstrate that the semiconducting nature of our AFM electrode allows us to perform anisotropic magnetoresistance measurements in the current-perpendicular-to-plane geometry without introducing a tunnel barrier into the stack. Temperature-dependent measurements of the resistance and anisotropic magnetoresistance highlight the large, entangled tunabilities of the ordinary charge and spin-dependent transport in a spintronic device utilizing the antiferromagnet semiconductor.

Antiferromagnetic hexagonal MnTe is a promising material for spintronic devices relying on the control of antiferromagnetic domain orientations. Here we report on neutron diffraction, magnetotransport, and magnetometry experiments on semiconducting epitaxial MnTe thin films together with density functional theory (DFT) calculations of the magnetic anisotropies. The easy axes of the magnetic moments within the hexagonal basal plane are determined to be along $〈1\overline{1}00〉$ directions. The spin-flop transition and concomitant repopulation of domains in strong magnetic fields is observed. Using epitaxially induced strain the onset of the spin-flop transition changes from $\sim 2$ to $\sim 0.5$ T for films grown on InP and ${\mathrm{SrF}}_2$ substrates, respectively.

A consistent picture on the mean-field level of the magnetic properties and electronic structure of the superconducting itinerant ferromagnet ${\mathrm{UGe}}_2$ requires inclusion of correlation effects beyond the local density approximation (LDA). The “ $\mathrm{LDA}+U$” approach reproduces both the magnitude of the observed moment and the magnetocrystalline anisotropy. The largest Fermi surface sheet is composed primarily of spin majority states with orbital projection $m_{\ell }=0\mathrm{}$, suggesting a much simpler picture of the pairing than is possible for general strong spin-orbit coupled materials. The quasi-two-dimensional geometry of the Fermi surface supports the likelihood of magnetically mediated $p$-wave triplet pairing.