Classical electromagnetic model of surface states in topological insulators
Classical electromagnetic model of surface states in topological insulators
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DOI：
10.1117/1.jnp.10.033004
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发表时间：
2016-01
影响因子：
1.5
通讯作者：
A. Lakhtakia;T. Mackay
中科院分区：
文献类型：
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作者：
A. Lakhtakia;T. Mackay
抽象的。拓扑绝缘体通常被建模为各向同性材料，其内部存在磁电赝标量 Ψ，而其表面不带电荷且不存在电流。另一种模型是通过设置 Ψ=0 并结合以导纳 γ 为特征的表面电荷和电流密度来获得的。对拓扑绝缘体半空间引起的平面波反射和折射的分析表明，参数 Ψ 和 γ 在反射和透射系数中出现相同，这意味着这两个经典模型无法在任何散射情况下区分。然而，由于 Ψ 从适用于拓扑绝缘体占据的任何区域的麦克斯韦方程中消失，并且由于表面态作为受保护的导电态存在于拓扑绝缘体上，因此必须选择替代模型。
Abstract. A topological insulator is classically modeled as an isotropic material with a magnetoelectric pseudoscalar Ψ existing in its bulk while its surface is charge free and current free. An alternative model is obtained by setting Ψ≡0 and incorporating surface charge and current densities characterized by an admittance γ. Analysis of planewave reflection and refraction due to a topological-insulator half space reveals that the parameters Ψ and γ arise identically in the reflection and transmission coefficients, implying that the two classical models cannot be distinguished on the basis of any scattering scenario. However, as Ψ disappears from the Maxwell equations applicable to any region occupied by the topological insulator, and because surface states exist on topological insulators as protected conducting states, the alternative model must be chosen.