The direct exchange mechanism of induced spin polarization of low-dimensional pi-conjugated carbon- and h-BN fragments at LSMO(001) MnO-terminated interfaces

Kuklin, AV; Kuzubov, AA; Kovaleva, EA; Lee, H; Sorokin, PB; Sakai, S; Entani, S; Naramoto, H; Avramov, P JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS, 440 23-29; Doi: 10.1016/j.jmmm.2016.12.096 OCT 15 2017

Induced spin polarization of π-conjugated carbon and h-BN low dimensional fragments at the interfaces formed by deposition of pentacene molecule and narrow zigzag graphene and h-BN nanoribbons on MnO2-terminated LSMO(001) thin film was studied using GGA PBE+U PAW D3-corrected approach. Induced spin polarization of π-conjugated low-dimensional fragments is caused by direct exchange with Mn ions of LSMO(001) MnO-derived surface. Due to direct exchange, the pentacene molecule changes its diamagnetic narrow-band gap semiconducting nature to the ferromagnetic semiconducting state with 0.15 eV energy shift between spin-up and spin-down valence bands and total magnetic moment of 0.11 μB. Direct exchange converts graphene nanoribbon to 100% spin-polarized half-metal with large amplitude of spin-up electronic density at the Fermi level. The direct exchange narrows the h-BN nanoribbon band gap from 4.04 to 1.72 eV in spin-up channel and converts the h-BN ribbon semiconducting diamagnetic nature to a semiconducting magnetic one. The electronic structure calculations demonstrate a possibility to control the spin properties of low-dimensional π-conjugated carbon and h-BN fragments by direct exchange with MnO-derived LSMO(001) surface for spin-related applications.