Oak Ridge National Laboratory, One Bethel Valley Road, Oak Ridge, Tennessee 37831-6493, United States.
Nano Lett. 2011 Aug 10;11(8):3267-73. doi: 10.1021/nl201616h. Epub 2011 Jul 20.
Standard spin-polarized density functional theory calculations have been conducted to study the electronic structures and magnetic properties of O and S functionalized zigzag boron nitride nanoribbons (zBNNRs). Unlike the semiconducting and nonmagnetic H edge-terminated zBNNRs, the O edge-terminated zBNNRs have two energetically degenerate magnetic ground states with a ferrimagnetic character on the B edge, both of which are metallic. In contrast, the S edge-terminated zBNNRs are nonmagnetic albeit still metallic. An intriguing coexistence of two different Peierls-like distortions is observed for S edge-termination that manifests as a strong S dimerization at the B zigzag edge and a weak S trimerization at the N zigzag edge, dictated by the band fillings at the vicinity of the Fermi level. Nevertheless, metallicity is retained along the S wire on the N edge due to the partial filling of the band derived from the p(z) orbital of S. A second type of functionalization with O or S atoms embedded in the center of zBNNRs yields semiconducting features. Detailed examination of both types of functionalized zBNNRs reveals that the p orbitals on O or S play a crucial role in mediating the electronic structures of the ribbons. We suggest that O and S functionalization of zBNNRs may open new routes toward practical electronic devices based on boron nitride materials.
采用标准的自旋极化密度泛函理论计算研究了 O 和 S 功能化的锯齿型氮化硼纳米带（zBNNRs）的电子结构和磁性。与具有半导体和非磁性 H 边缘终止的 zBNNRs 不同，O 边缘终止的 zBNNRs 具有两个能量简并的磁基态，在 B 边缘具有铁磁特性，两者均为金属。相比之下，S 边缘终止的 zBNNRs 虽然仍是金属但却没有磁性。有趣的是，S 边缘终止存在两种不同的类 Peierls 畸变的共存，表现为在 B 锯齿边缘强烈的 S 二聚化和在 N 锯齿边缘较弱的 S 三聚化，这是由费米能级附近的能带填充决定的。然而，由于 S 原子的 p(z)轨道导致的能带部分填充，N 边缘上的 S 线上仍保持金属性。在 zBNNRs 的中心嵌入 O 或 S 原子的第二种功能化也产生了半导体特性。对这两种功能化的 zBNNRs 的详细研究表明，O 或 S 上的 p 轨道在调节带的电子结构方面起着至关重要的作用。我们认为，zBNNRs 的 O 和 S 功能化可能为基于氮化硼材料的实际电子器件开辟新途径。
