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arXiv 2202.05640cond-mat.mes-hallcond-mat.mtrl-scicond-mat.other
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多壁拓扑异质结构中界面态与质量态的相互作用

Interaction between interface and massive states in multivalley topological heterostructures

Gauthier Krizman, Badih A. Assaf, Milan Orlita, Guenther Bauer, Gunther Springholz, Robson Ferreira, Louis-Anne de Vaulchier, Yves Guldner

摘要:

研究了多通道系统中的拓扑界面态,揭示了它们的谷值敏感性。为此目的,多路IV-VI拓扑晶体绝缘体(TCI)异质结构探索使用磁光朗道能级光谱高达34特斯拉。我们研究了沿[111]方向生长的Pb_(1-x)Sn_xSe多量子阱中不同L谷的拓扑界面态.结果表明,TCI/平凡绝缘体界面处拓扑界面态的二维费米面的形状受拓扑平凡Pb 1-yEuySe势垒的谷各向异性的强烈影响.这种现象被证明是由于深入渗透到势垒的拓扑界面状态。对于相对于限制方向倾斜的谷,观察到拓扑状态和传统的大质量量子阱状态之间的显着相互作用,证明了由此产生的大的反交叉朗道能级之间。这些理论上是很好地描述了一个k.p模型,考虑到倾斜和各向异性的山谷在两个维度。因此,我们的工作提供了一个精确的表征拓扑界面态谷分裂,以及准确的测定其狄拉克锥色散的各向异性。

英文摘要:

Topological interface states in multivalley systems are studied to unravel their valley sensitivity. For this purpose, multivalley IV-VI topological crystalline insulator (TCI) heterostructures are explored using magneto-optical Landau level spectroscopy up to 34 teslas. We characterize the topological interface states emerging from the distinct L-valleys in Pb1-xSnxSe multi quantum wells grown along the [111] direction. It is shown that the shape of the 2D Fermi surfaces of topological interface states residing at the TCI/trivial insulator interfaces are strongly affected by the valley anisotropy of topologically trivial Pb1-yEuySe barriers. This phenomenon is shown to be due to the deep penetration of the topological interface states into the barriers. For the valleys tilted with respect to the confinement direction, a significant interaction between topological states and the conventional massive quantum well states is observed, evidenced by the resulting large anti-crossings between Landau levels. These are theoretically well-described by a k.p model that takes into account tilt and anisotropy of the valleys in two dimensions. Therefore, our work provides a precise characterization of the topological interface state valley splitting, as well as an accurate determination of the anisotropy of their Dirac cone dispersion.

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