Shadow surface states in topological Kondo insulators
Shadow surface states in topological Kondo insulators
复制标题
拓扑近藤绝缘体中的阴影表面状态
DOI：
10.1088/1367-2630/ac4124
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发表时间：
2021
影响因子：
3.3
通讯作者：
Ghaemi, Pouyan
中科院分区：
文献类型：
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作者：
Ghazaryan, Areg;Nica, Emilian M.;Erten, Onur;Ghaemi, Pouyan
当化学势调整到狄拉克点时，3D 拓扑绝缘体的表面态通常具有可忽略的量子振荡 (QO)。相比之下，我们发现当化学势固定在狄拉克点时，拓扑近藤绝缘体（TKI）可以支持具有任意大费米面（FS）的表面态。我们说明这些 FS 产生了有限频率 QO，它可以与未混合体频带的极值区域进行比较。我们证明，当晶体对称性在最小二轨道模型中从立方体降低到四方体时，就会发生这种情况。我们将这种表面模式标记为“阴影表面状态”。此外，我们表明，对于四方 TKI，足够的次近邻面外杂化导致阴影表面态可以自洽稳定。因此，阴影表面状态提供了三次 TKI 之外的高频 QO 的重要示例。
The surface states of 3D topological insulators in general have negligible quantum oscillations (QOs) when the chemical potential is tuned to the Dirac points. In contrast, we find that topological Kondo insulators (TKIs) can support surface states with an arbitrarily large Fermi surface (FS) when the chemical potential is pinned to the Dirac point. We illustrate that these FSs give rise to finite-frequency QOs, which can become comparable to the extremal area of the unhybridized bulk bands. We show that this occurs when the crystal symmetry is lowered from cubic to tetragonal in a minimal two-orbital model. We label such surface modes as' shadow surface states'. Moreover, we show that the sufficient next-nearest neighbor out-of-plane hybridization leading to shadow surface states can be self-consistently stabilized for tetragonal TKIs. Consequently, shadow surface states provide an important example of high-frequency QOs beyond the context of cubic TKIs.