Control of Giant Topological Magnetic Moment and Valley Splitting in Trilayer Graphene,Physical Review Letters

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Control of Giant Topological Magnetic Moment and Valley Splitting in Trilayer Graphene
Physical Review Letters ( IF 8.1 ) Pub Date : 2021-09-23 , DOI: 10.1103/physrevlett.127.136402
Zhehao Ge ₁ , Sergey Slizovskiy _{2,

3} , Frédéric Joucken ₁ , Eberth A Quezada ₁ , Takashi Taniguchi ₄ , Kenji Watanabe ₅ , Vladimir I Fal'ko _{2,

3,

6} , Jairo Velasco ₁

Affiliation

Bloch states of electrons in honeycomb two-dimensional crystals with multivalley band structure and broken inversion symmetry have orbital magnetic moments of a topological nature. In crystals with two degenerate valleys, a perpendicular magnetic field lifts the valley degeneracy via a Zeeman effect due to these magnetic moments, leading to magnetoelectric effects which can be leveraged for creating valleytronic devices. In this work, we demonstrate that trilayer graphene with Bernal stacking (ABA TLG), hosts topological magnetic moments with a large and widely tunable valley

g

factor (

g_{ν}

), reaching a value

g_{ν} \sim 1050

at the extreme of the studied parametric range. The reported experiment consists in sublattice-resolved scanning tunneling spectroscopy under perpendicular electric and magnetic fields that control the TLG bands. The tunneling spectra agree very well with the results of theoretical modeling that includes the full details of the TLG tight-binding model and accounts for a quantum-dot-like potential profile formed electrostatically under the scanning tunneling microscope tip.

中文翻译：

三层石墨烯中巨拓扑磁矩和谷分裂的控制

具有多谷能带结构和破坏反转对称性的蜂窝二维晶体中电子的布洛赫态具有拓扑性质的轨道磁矩。在具有两个简并谷的晶体中，由于这些磁矩，垂直磁场通过塞曼效应提升谷简并，导致磁电效应，可用于创建谷电子器件。在这项工作中，我们证明了具有伯纳尔堆积 (ABA TLG) 的三层石墨烯具有具有大且广泛可调的谷的拓扑磁矩