Quasiparticle dynamics in reshaped helical Dirac cone of topological insulators
Quasiparticle dynamics in reshaped helical Dirac cone of topological insulators
复制标题
拓扑绝缘体重塑螺旋狄拉克锥中的准粒子动力学
DOI：
10.1073/pnas.1218104110
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发表时间：
2013-02-19
影响因子：
11.1
通讯作者：
Jia, Jin-Feng
中科院分区：
文献类型：
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作者：
Miao, Lin;Wang, Z. F.;Jia, Jin-Feng
拓扑绝缘体和石墨烯呈现出两类独特的材料，其特征分别是自旋极化（螺旋）和非极化狄拉克锥带结构。多体相互作用对石墨烯中狄拉克点附近的线性带进行重新归一化的重要性已得到充分认识，并引起了最近的广泛关注。然而，在拓扑绝缘体中尚未观察到螺旋狄拉克点的重正化。在这里，我们报告了通过角分辨光电子能谱在 Bi2Te3 衬底上生长的单个 Bi 双层中使用倾斜狄拉克锥的重正化准粒子光谱的实验观察。第一原理能带计算表明，准粒子光谱可能与 Bi 双层的外在基质诱导的狄拉克态和 Bi2Te3 薄膜的本征表面狄拉克态在能量接近时的杂化有关。如果没有这种杂化，在 Bi2Se3 上生长的单个 Bi 双层中只能观察到单粒子狄拉克光谱，其中外在狄拉克态 Bi 双层和 Bi2Se3 的内在狄拉克态在能量上很好地分离。讨论了多体相互作用的可能起源。我们的发现提供了一种操纵拓扑表面状态的方法。
Topological insulators and graphene present two unique classes of materials, which are characterized by spin-polarized (helical) and nonpolarized Dirac cone band structures, respectively. The importance of many-body interactions that renormalize the linear bands near Dirac point in graphene has been well recognized and attracted much recent attention. However, renormalization of the helical Dirac point has not been observed in topological insulators. Here, we report the experimental observation of the renormalized quasiparticle spectrum with a skewed Dirac cone in a single Bi bilayer grown on Bi2Te3 substrate from angle-resolved photoemission spectroscopy. First-principles band calculations indicate that the quasiparticle spectra are likely associated with the hybridization between the extrinsic substrate-induced Dirac states of Bi bilayer and the intrinsic surface Dirac states of Bi2Te3 film at close energy proximity. Without such hybridization, only single-particle Dirac spectra are observed in a single Bi bilayer grown on Bi2Se3, where the extrinsic Dirac states Bi bilayer and the intrinsic Dirac states of Bi2Se3 are well separated in energy. The possible origins of many-body interactions are discussed. Our findings provide a means to manipulate topological surface states.