Creation of helical Dirac fermions by interfacing two gapped systems of ordinary fermions
Creation of helical Dirac fermions by interfacing two gapped systems of ordinary fermions
复制标题
通过连接普通费米子的两个带隙系统创建螺旋狄拉克费米子
DOI：
10.1038/ncomms2387
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发表时间：
2013-01-01
影响因子：
16.6
通讯作者：
Liu, Feng
中科院分区：
文献类型：
--
作者：
Wang, Z. F.;Yao, Meng-Yu;Liu, Feng
拓扑绝缘体是一类独特的材料，其特征在于螺旋狄拉克费米子在体隙中间的狄拉克锥态。然而，当三维拓扑绝缘体的厚度减小时，相反的表面态之间的相互作用打开了一个间隙，消除了螺旋狄拉克锥，将材料转换回普通费米子的正常系统。在这里，我们证明，使用密度泛函理论计算和实验，它是可能的，创建螺旋狄拉克费米子状态的接口两个带隙薄膜-一个单一的双层Bi生长在一个单一的五重层Bi 2 Se 3或Bi 2 Te 3。这些非本征螺旋狄拉克费米子主要出现在Bi双层态，这是由巨大的Rashba效应产生的，耦合常数类似于4 eV。埃由于界面电荷转移。我们的研究结果表明，这种方法是一种很有前途的手段工程拓扑绝缘体状态的非金属表面。
Topological insulators are a unique class of materials characterized by a Dirac cone state of helical Dirac fermions in the middle of a bulk gap. When the thickness of a three-dimensional topological insulator is reduced, however, the interaction between opposing surface states opens a gap that removes the helical Dirac cone, converting the material back to a normal system of ordinary fermions. Here we demonstrate, using density function theory calculations and experiments, that it is possible to create helical Dirac fermion state by interfacing two gapped films-a single bilayer Bi grown on a single quintuple layer Bi2Se3 or Bi2Te3. These extrinsic helical Dirac fermions emerge in predominantly Bi bilayer states, which are created by a giant Rashba effect with a coupling constant of similar to 4eV . angstrom due to interfacial charge transfer. Our results suggest that this approach is a promising means to engineer topological insulator states on non-metallic surfaces.