Enhanced half-metallicity in edge-oxidized zigzag graphene nanoribbons
Enhanced half-metallicity in edge-oxidized zigzag graphene nanoribbons
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DOI：
10.1021/ni0708922
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发表时间：
2007-08-01
期刊：
影响因子：
10.8
通讯作者：
Scuseria, Gustavo E.
中科院分区：
文献类型：
--
作者：
Hod, Oded;Barone, Veronica;Scuseria, Gustavo E.
我们提出了一个全面的理论研究的电子性质和相对稳定性的边缘氧化锯齿形石墨烯纳米带。考虑的氧化方案包括羟基、内酯、酮和醚基。使用屏蔽交换密度泛函理论，我们表明，这些氧化带比氢封端的纳米带更稳定，除了醚基团的情况下。稳定的氧化配置保持自旋极化的基态与反铁磁有序定位在边缘，类似于完全氢化的同行。更重要的是，边缘氧化被发现，以降低所需的发病电场诱导半金属的行为和扩展的整体领域的范围内，系统保持半金属。一旦达到半金属状态，外部电场强度的进一步增加会使自旋磁化强度迅速下降，直到磁化强度完全淬灭。最后，我们发现含氧边缘基团对反铁磁基态和上面铁磁态之间的能量差的影响很小。
We present a comprehensive theoretical study of the electronic properties and relative stabilities of edge-oxidized zigzag graphene nanoribbons. The oxidation schemes considered include hydroxyl, lactone, ketone, and ether groups. Using screened exchange density functional theory, we show that these oxidized ribbons are more stable than hydrogen-terminated nanoribbons except for the case of the etheric groups. The stable oxidized configurations maintain a spin-polarized ground state with antiferromagnetic ordering localized at the edges, similar to the fully hydrogenated counterparts. More important, edge oxidation is found to lower the onset electric field required to induce half-metallic behavior and extend the overall field range at which the systems remain half-metallic. Once the half-metallic state is reached, further increase of the external electric field intensity produces a rapid decrease in the spin magnetization up to a point where the magnetization is quenched completely. Finally, we find that oxygen-containing edge groups have a minor effect on the energy difference between the antiferromagnetic ground state and the above-lying ferromagnetic state.