Parashu Kharel | Searcharxiv

arXiv2026

Key Role of Charge Disproportionation in Monoclinic Semiconducting Fe$_2$PO$_5$, a Room-Temperature d-Wave Altermagnet Candidate

$β$-Fe$_2$PO$_5$ is an emerging room-temperature d-wave altermagnet featuring quasi-one-dimensional crystal and magnetic structures, orthogonal transport channels for opposite spins, and large band spin splitting, which is a promising material for next-generation spintronics and magnonics. However, its crystal and electronic structures remain inconclusive. Here, joint experimental and theoretical studies confirm and explain the appearance of its monoclinic structure and semiconducting band gap. We discover that an electronic instability appears in the tetragonal metallic state as the joint effect of density functional theory and Hubbard U correction (DFT+U) and results in a charge disproportionation, which in turn stabilizes the monoclinic distortion with narrow gap formation. The successful capture of this effect within DFT+U requires accounting for the relevant symmetry-breaking energy-lowering channels -- charge disproportionation and structural distortion; otherwise, tetragonal-symmetry-constrained calculations yield only a metallic state. Fe$_2$PO$_5$ is thus best described as a correlation- and hybridization-assisted, distortion-coupled, charge-disproportionated semiconductor. It represents a rare room-temperature semiconducting d-wave altermagnet. It also provides a rare platform for studying the coexistence of altermagnetism and charge density wave in quasi-one-dimensional systems.

cond-mat.mtrl-sci↗

arXiv2021

Computational Optimization of MnBi to Enhance Energy Product

High energy density magnets are preferred over induction magnets for many applications, including electric motors used in flying rovers, electric vehicles, and wind turbines. However, several issues related to cost and supply with state-of-the-art rare-earth-based magnet necessities development of high-flux magnets containing low cost, earth-abundant materials. Here, we demonstrate the possibility of tuning magnetization and magnetocrystalline anisotropy of one of the candidate materials, MnBi, by alloying it with foreign elements. By using the density functional theory in the high-throughput fashion, we consider the possibility of alloying MnBi with all possible metal and non-metal elements in the periodic table and found that MnBi-based alloys with Pd, Pt, Rh, Li, and O are stable against decomposition to constituent elements and have larger magnetization, energy product compared and magnetic anisotropy compared to MnBi We consider the possibility of these elements occupying half and all of the available empty sites. Combined with other favorable properties of MnBi, such as high Curie temperature and earth abundancy of constituents elements, we envision the possibility of MnBi-based high-energy-density magnets.

cond-mat.mtrl-sci↗