第一性原理对二碲化钨的纳米带电子结构性质的预测研究
首发时间:2018-06-11
摘要:当二维材料的尺寸缩小至纳米级别时,其物理与电子特性会显著改变。通过把 2H 和 当二维材料的尺寸缩小至纳米级别时,其物理与电子特性会显著改变。通过把 2H 和Td 相的二维过渡金属硫化物二碲化钨((WTe2 ) 裁剪至一维纳米带,我们得到了几种新的边缘结构,因为量子霍尔效应的影响,得到的结构极大的影响了电子结构。用第一性原理计算电子结构,我们在 2H 相的 armchair 方向纳米带中中得到了一个带隙在 0-0.32 eV 的直接带隙,在Td 相的 X 方向纳米带中得到了 0-0.27 eV 的直接带隙。而 2H 相的 Zigzag 纳米带和 Td 相的Y 方向纳米带都保持了金属特性。引用边界能描述纳米带边界的稳定性,并得到半晶格填充的Y 方向纳米带最稳定。总之,通过边界原子的成键和空缺,不同别界的 WTe2 纳米带表现了非常特殊的性质。
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First-principles predictions of the geometries and electronic structures of tungsten ditelluride nanoribbons
Abstract:When the size of two-dimensional materials minifies to quantum, the mechanical and electronic properties affected significantly. By cutting 2H and Td phase two-dimensional Tungsten telluride (WTe2 ), a layered transition-metal chalcogenide (TMD C ), to nanoribbons(NRs), we got several new edge structure. The nontrivial edge states be closely linked to quantum spin Hall (QSH) effect.Using first principles, we calculate the electronic structure and get controllable band gap.There data suggest a 0-0.32 eV indirect band gap in armchair direction of 2H-WTe2 and 0-0.27 eV in X direction of Td-WTe2 sheet of different widths.However, Zigzag direction of 2H-WTe2 and Y direction of Td-WTe2 keep the metal character. Edge energy is quoted to describe stability of nanoribbon’s boundary structure. we demonstrate that semi-lattice phase of Td-WTe2 Y direction has smallest edge energy, indicating Td y -WTe2 is most stable. In a word, different boundaries of WTe2 present peculiar property and further confirm that border atoms determine the properties of the ribbons with deficiency of bonding.
Keywords: First principle WTe2 Nanoribbons
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第一性原理对二碲化钨的纳米带电子结构性质的预测研究
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