Nonlocal Transport in the Quantum Spin Hall State

By A. Roth, C. Brüne, H. Buhmann, L. Molenkamp, J. Maciejko, Xiao-Liang Qi, Shoucheng Zhang. Science, 2009

661 citations recorded by the source corpus.

Living on the Edge Topological insulators are a recently described state of matter in which the bulk material is an insulator but with a metallic surface state that is protected by the topology of the Fermi surface. Roth et al. (p. 294; see the Perspective by Büttiker) now show that the current flow on the surface takes place in edge states around the boundary of the sample. These are similar to the current transport in high-quality two-dimensional electron gases in high magnetic field, which confirms theoretical work on these materials. A topological insulator exhibits current flow in edge states around the sample without the need for magnetic fields. Nonlocal transport through edge channels holds great promise for low-power information processing. However, edge channels have so far only been demonstrated to occur in the quantum Hall regime, at high magnetic fields. We found that mercury telluride quantum wells in the quantum spin Hall regime exhibit nonlocal edge channel transport at zero external magnetic field. The data confirm that the quantum transport through the (helical) edge channels is dissipationless and that the contacts lead to equilibration between the counterpropagating spin states at the edge. The experimental data agree quantitatively with the theory of the quantum spin Hall effect. The edge channel transport paves the way for a new generation of spintronic devices for low-power information processing.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/0ba773715b8af7c97ec026d46d58774852dedb13

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Atomic and Molecular Physics, and Optics

1. A. Manchon
2. Ivar Martin
3. H. Buhmann
4. Junsaku Nitta
5. S. Frolov
6. Jian Li
7. Chaoxing Liu
8. A. Morpurgo

In Materials Chemistry

1. Ivar Martin
2. H. Buhmann
3. Yang Ding
4. Junsaku Nitta
5. S. Frolov
6. Lin Wang
7. Bing Li
8. Jian Li

Citations in the corpus

• Topological origin of subgap conductance in insulating bilayer graphene (2010, background): “These properties of BLG parallel those of spin-orbit induced topological insulators [18–21], in which ballistic helical edge states have been observed experimentally [22, 23], but with the valley quantum number playing the role of the electron spin.”
• New perspectives for Rashba spin-orbit coupling. (2015, background): “Interestingly, the quantum spin Hall effect is accompanied by spin-polarized edge currents similar to the ones observed in topological insulators [87], [114].”
• Single valley Dirac fermions in zero-gap HgTe quantum wells (2010, background): “, boasting dissipationless edge channel transport at zero external magnetic fiel”
• Induced superconductivity in the quantum spin Hall edge (2013, background): “This topological phase of matter was recently predicted [20, 21] and observed [22, 23] in HgTe/HgCdTe quantum wells thicker than a critical thickness dC = 6.”
• Solids, liquids, and gases under high pressure (2018, background): “Such interesting characteristics have been well determined in two-dimensional HgCdTe quantum (Roth et al., 2009), three-dimensional crystals of Bi1−xSbx (Hsieh et al., 2008), and the group VI-V binary compounds Bi2Se3 (Xia et al., 2009), Bi2Te3 (Chen et al., 2009), and Sb2Te3 (Hsieh et al., 2009).”