Avramov Paul, Kuzubov Alexander A, Kuklin Artem V, Lee Hyosun, Kovaleva Evgenia A, Sakai Seiji, Entani Shiro, Naramoto Hiroshi, Sorokin Pavel B
Department of Chemistry and Green-Nano Materials Research Center, Kyungpook National University , 80 Daehak-ro, Buk-gu, Daegu, 41566, Republic of Korea.
Siberian Federal University , 79 Svobodniy pr., Krasnoyarsk 660041, Russia.
J Phys Chem A. 2017 Jan 26;121(3):680-689. doi: 10.1021/acs.jpca.6b09696. Epub 2017 Jan 11.
The structure of the interfaces and the mechanisms of induced spin polarization of 1D infinite and finite narrow graphene- and h-BN zigzag nanoribbons placed on a SrO-terminated LaSrMnO (LSMO) (001) surface were studied using density functional theory (DFT) electronic structure calculations. It was found that the π-conjugated nanofragments are bonded to the LSMO(001) surface by weak disperse interactions. The types of coordination of the fragments, the strength of bonding, and the rate of spin polarization depend upon the nature of the fragments. Infinite and finite graphene narrow zigzag nanoribbons are characterized by the lift of the spin degeneracy and strong spin polarization caused by interface-induced structural asymmetry and oxygen-mediated indirect exchange interactions with Mn ions of LSMO support. Spin polarization changes the semiconducting nature of infinite graphene nanoribbons to half-metallic state with visible spin-up density of states at the Fermi level. The h-BN nanoribbon binding energy is weaker than graphene nanoribbon ones with noticeably shorter interlayer distance. The asymmetry effect and indirect exchange interactions cause spin polarization of h-BN nanoribbon as well with formation of embedded states inside the band gap. The results show a possibility to use one-atom thick nanofragments to design LSMO-based heterostructures for spintronic nanodevices with h-BN as an inert spacer to develop different potential barriers.
利用密度泛函理论（DFT）电子结构计算，研究了置于SrO端接的LaSrMnO（LSMO）（001）表面上的一维无限和有限窄石墨烯及六方氮化硼锯齿形纳米带的界面结构和诱导自旋极化机制。研究发现，π共轭纳米片段通过弱色散相互作用与LSMO（001）表面键合。片段的配位类型、键合强度和自旋极化速率取决于片段的性质。无限和有限的石墨烯窄锯齿形纳米带的特征在于自旋简并的解除以及由界面诱导的结构不对称和与LSMO载体的Mn离子的氧介导间接交换相互作用引起的强自旋极化。自旋极化将无限石墨烯纳米带的半导体性质转变为半金属态，在费米能级处具有明显的自旋向上态密度。六方氮化硼纳米带的结合能比石墨烯纳米带的弱，层间距离明显更短。不对称效应和间接交换相互作用也导致六方氮化硼纳米带的自旋极化，并在带隙内形成嵌入态。结果表明，有可能使用单原子厚的纳米片段来设计基于LSMO的异质结构，用于自旋电子纳米器件，以六方氮化硼作为惰性间隔层来开发不同的势垒。
