Ferromagnetism in Monatomic Chains: Spin-Dependent Bandwidth Narrowing/Broadening

Abstract

We have analyzed the role of band narrowing/broadening in the magnetic and electronic properties of low dimensional itinerant strongly correlated electronic systems, which is particularly important in 3d transition elements. Density functional theory and mean field results have been coupled to explain the magnetic phenomenon in a one-dimensional monatomic chain of 3d transition elements Sc, Ti, V, Cr, Mn, Fe, Co, and Ni. We found that in the ferromagnetic ground state not only the band splitting but also the relative band narrowing/broadening play a crucial role, and the bandwidths of both spins become different as a manifestation of correlated spin hopping interaction. For less than the half-filled band (i.e., for Sc, Ti, V, and Cr), the up spin band broadens, and the down spin band narrows. For the (half and) more than half filled band (i.e., for Mn, Fe, Co, and Ni), the down spin band broadens, and the up spin band narrows. As a result, (in most of the cases) only one spin channel is present for conduction, showing ferromagnetism which could be useful for spintronics.

Indirect-To-Direct Band Gap Transition of One-Dimensional V2Se9: Theoretical Study with Dispersion Energy Correction

“…12 The reduction of dimensionality also can influence the charge transfer, the structure of the crystal, spin property, or the charge carrier mobility in the metal nanowire system. 13−19…”

“…Other 2D materials with appropriate band gaps, including transition-metal dichalcogenides (TMDCs) and black phosphorus, have been introduced. − Similar to graphene, a dramatic reduction in charge carrier mobility due to edge scattering is inevitable after device manufacture . The reduction of dimensionality also can influence the charge transfer, the structure of the crystal, spin property, or the charge carrier mobility in the metal nanowire system. − …”

Direct growth of single-metal-atom chains

“…Introduction: Single-metal-atom chains (SMACs), known as one of the smallest onedimensional structures, have garnered broad research interest, attributing to their unique properties, such as quantized conductance, thermal transport, charge/spin density waves, and peculiar magnetic properties, as well as distinct catalytic properties. [1][2][3][4][5][6] For example, it was reported that the average bond strength in the chain is twice that of the bulk counterpart 7 . Up to now, several SMACs like Au, Ir, and Pt chains have been fabricated by using a top-down mechanical break junction (MBJ) method, showing quantum ballistic transport 8,9 , anisotropic magnetoresistance 10,11 , and the Kondo effect 12 .…”

Singular Nonmagnetic Semiconductor ScH3 Molecular Nanowire: A New Type of Room-Temperature Spintronic Material

“…Due to its great potential in significantly increasing the data-processing speed and integration density, spintronics has attracted more and more research attention. − To construct practical spintronic devices, the choice of spintronic materials is crucial. So far, a lot of spintronic materials have been studied, − such as a half-metal, , which is any substance that acts like a metal in one spin channel and a semiconductor in the other spin channel and can provide completely spin-polarized currents. Recently, d 0 ferromagnetism has attracted great attention. − As an example, in 2018, Chakraborty et al found that carbon-doped Y 2 O 3 shows room-temperature d 0 ferromagnetism.…”