Electronic structure and magnetism in M(=IA, IIA)C compounds with the rocksalt structure

Abstract

Electronic structures of MC where M is the alkali and alkaline earth metals with the rocksalt structure are calculated by full potential density functional codes. We find that the spin magnetic moment in the compounds is mainly contributed by the spin polarized p-orbitals of carbon. The large distance between the carbon makes the p-orbitals localized, which induces magnetic instability according to the Stoner criterion. The electronic structure can be mapped to the rigid band model. SrC, BaC and RaC are half-metals, while KC, RbC and CsC are magnetic semiconductors.

First-principles study of mechanical, vibrational and thermodynamic properties of magnetic XC compounds (X = Rb, Sr)

“…As seen, the RbC is found to be semiconductor with fully spin polarized 2p states, whereas SrC is half-metal. These results are in good agreement with previous work on carbides compounds [15]. The total polarization of p-C states at the Fermi level demonstrates the sp-hybridization type.…”

“…This new class is based on alkali and alkaline earth metal elements, where the magnetic order is realized by the polarization of p-empty states without any direct contribution of d-electrons. Previous studies on alkali and alkaline earth metals with V-and VI-elements predicted half-metallicity with ferromagnetic order in various structures [5][6][7][8][9][10][11][12][13][14][15][16]. The total magnetic moment takes an integer value depending on the empty states at the Fermi level.…”

Magnetism in RbxSr1-xC novel alloy

“…According to the studies undertaken in this field, these materials could be serious candidates in the spintronic field. Previous works cover binary compounds with V-and VI-elements and confirm half-metallicity with ferromagnetic ordering [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]. In particular, carbon-based compounds exhibit ferromagnetism in various structures as binaries [6,9,12,14,16] and also as heusler-type structures [18,19].…”

“…According to the paper of Zhang et al [16] and Lakdja et al [20], the SrC compound is found to be a half-metal, whereas the RbC compound is a semiconductor. There was suggested a possibility to have half-metallicity by doping alkali compounds with alkaline earth or vice versa [16]. This was the main source of motivation to study the Rb x Sr 1−x C alloy.…”

First-principles and molecular dynamics studies on structural, electronic, and magnetic characteristics of (CaC)1/(SiC)1and (KC)1/(SiC)1in wurtzite structure

“…Nevertheless, a novel class of magnetic compounds containing neither transition metals nor rare‐earth elements, known as sp magnets, has been explored in the past several years. Ferromagnetic coupling was found in several binary I A –III A , I A –IV A , I A –V A , I A –VI A , II A –IV A , and II A –V A compounds with several simple crystalline phases such as rock‐salt, zinc‐blende, and wurtzite structures . The lack of experimental data in the case of these sp ‐magnetic compounds relates to the difficulties in fabricating such crystals.…”