article published yes Ersoy Şaşıoğlu author Arno Schindlmayr author 4580000-0002-4855-071X Christoph Friedrich author Frank Freimuth author Stefan Blügel author 296 department 35 department 15 department 170 department 230 department We present a computational scheme to study spin excitations in magnetic materials from first principles. The central quantity is the transverse spin susceptibility, from which the complete excitation spectrum, including single-particle spin-flip Stoner excitations and collective spin-wave modes, can be obtained. The susceptibility is derived from many-body perturbation theory and includes dynamic correlation through a summation over ladder diagrams that describe the coupling of electrons and holes with opposite spins. In contrast to earlier studies, we do not use a model potential with adjustable parameters for the electron-hole interaction but employ the random-phase approximation. To reduce the numerical cost for the calculation of the four-point scattering matrix we perform a projection onto maximally localized Wannier functions, which allows us to truncate the matrix efficiently by exploiting the short spatial range of electronic correlation in the partially filled d or f orbitals. Our implementation is based on the full-potential linearized augmented-plane-wave method. Starting from a ground-state calculation within the local-spin-density approximation (LSDA), we first analyze the matrix elements of the screened Coulomb potential in the Wannier basis for the 3d transition-metal series. In particular, we discuss the differences between a constrained nonmagnetic and a proper spin-polarized treatment for the ferromagnets Fe, Co, and Ni. The spectrum of single-particle and collective spin excitations in fcc Ni is then studied in detail. The calculated spin-wave dispersion is in good overall agreement with experimental data and contains both an acoustic and an optical branch for intermediate wave vectors along the [100] direction. In addition, we find evidence for a similar double-peak structure in the spectral function along the [111] direction. To investigate the influence of static correlation we finally consider LSDA+U as an alternative starting point and show that, together with an improved description of the Fermi surface, it yields a more accurate quantitative value for the spin-wave stiffness constant, which is overestimated in the LSDA. https://ris.uni-paderborn.de/download/18560/18561/PhysRevB.81.054434.pdf application/pdfno American Physical Society2010 eng 1098-0121 1550-235X 1002.4897 00027499800008410.1103/PhysRevB.81.054434 815 E. Şaşıoğlu, A. Schindlmayr, C. Friedrich, F. Freimuth, and S. Blügel, “Wannier-function approach to spin excitations in solids,” <i>Physical Review B</i>, vol. 81, no. 5, Art. no. 054434, 2010, doi: <a href="https://doi.org/10.1103/PhysRevB.81.054434">10.1103/PhysRevB.81.054434</a>. Şaşıoğlu, E., Schindlmayr, A., Friedrich, C., Freimuth, F., &#38; Blügel, S. (2010). Wannier-function approach to spin excitations in solids. <i>Physical Review B</i>, <i>81</i>(5), Article 054434. <a href="https://doi.org/10.1103/PhysRevB.81.054434">https://doi.org/10.1103/PhysRevB.81.054434</a> Şaşıoğlu, Ersoy, et al. “Wannier-Function Approach to Spin Excitations in Solids.” <i>Physical Review B</i>, vol. 81, no. 5, 054434, American Physical Society, 2010, doi:<a href="https://doi.org/10.1103/PhysRevB.81.054434">10.1103/PhysRevB.81.054434</a>. @article{Şaşıoğlu_Schindlmayr_Friedrich_Freimuth_Blügel_2010, title={Wannier-function approach to spin excitations in solids}, volume={81}, DOI={<a href="https://doi.org/10.1103/PhysRevB.81.054434">10.1103/PhysRevB.81.054434</a>}, number={5054434}, journal={Physical Review B}, publisher={American Physical Society}, author={Şaşıoğlu, Ersoy and Schindlmayr, Arno and Friedrich, Christoph and Freimuth, Frank and Blügel, Stefan}, year={2010} } Şaşıoğlu E, Schindlmayr A, Friedrich C, Freimuth F, Blügel S. Wannier-function approach to spin excitations in solids. <i>Physical Review B</i>. 2010;81(5). doi:<a href="https://doi.org/10.1103/PhysRevB.81.054434">10.1103/PhysRevB.81.054434</a> E. Şaşıoğlu, A. Schindlmayr, C. Friedrich, F. Freimuth, S. Blügel, Physical Review B 81 (2010). Şaşıoğlu, Ersoy, Arno Schindlmayr, Christoph Friedrich, Frank Freimuth, and Stefan Blügel. “Wannier-Function Approach to Spin Excitations in Solids.” <i>Physical Review B</i> 81, no. 5 (2010). <a href="https://doi.org/10.1103/PhysRevB.81.054434">https://doi.org/10.1103/PhysRevB.81.054434</a>. 185602020-08-28T11:31:26Z2025-12-16T11:09:51Z