One-dimensional topologically protected modes in topological insulators with lattice dislocations

By Ying Ran, Yi Zhang, Ashvin Vishwanath. 2008

370 citations recorded by the source corpus.

Topological defects, such as domain walls and vortices, have long fascinated physicists. A novel twist is added in quantum systems such as the B-phase of superfluid helium He3, where vortices are associated with low-energy excitations in the cores. Similarly, cosmic strings may be tied to propagating fermion modes. Can analogous phenomena occur in crystalline solids that host a plethora of topological defects? Here, we show that indeed dislocation lines are associated with one-dimensional fermionic excitations in a ‘topological insulator’, a novel phase of matter believed to be realized in the material Bi0.9Sb0.1. In contrast to fermionic excitations in a regular quantum wire, these modes are topologically protected and not scattered by disorder. As dislocations are ubiquitous in real materials, these excitations could dominate spin and charge transport in topological insulators. Our results provide a novel route to creating a potentially ideal quantum wire in a bulk solid. Topological insulators are band insulators in which spin–orbit coupling takes the role of the applied magnetic field in the integer quantum Hall effect. Theory now predicts that dislocations in such systems can give rise to one-dimensional topologically protected states, resembling helical modes at the edge of a two-dimensional quantum spin Hall insulator.

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

View Paper: https://www.semanticscholar.org/paper/3aee8a8af115394501253befa9b81971ffabe0c1

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. J. Moore
2. M. Zahid Hasan
3. Hsin Lin
4. Arun Bansil
5. Xiao-Liang Qi
6. R. Cava
7. Ashvin Vishwanath
8. Y. Ando

In Materials Chemistry

1. M. Zahid Hasan
2. J. Moore
3. Hsin Lin
4. Arun Bansil
5. Xiao-Liang Qi
6. R. Cava
7. Ramamoorthy Ramesh
8. Y. Chu

Citations in the corpus

• The birth of topological insulators (2010, background): “In weak topological insulators, a dislocation (a line-like defect in the crystal) will always contain a quantum wire like that at the edge of the quantum spin Hall effect (discussed earlier), which may allow 2D topological insulator physics to be observed in a 3D materia”
• Topological active matter (2020, background): “Topological defects and topologically protected modes (such as chiral edge states) are intertwined 21–24 .”
• Quantization of fractional corner charge in Cn -symmetric higher-order topological crystalline insulators (2018, background): “[68] Ying Ran, Yi Zhang, and Ashvin Vishwanath, “Onedimensional topologically protected modes in topological insulators with lattice dislocations,” Nat Phys 5, 298–303 (2009).”
• Discovery (theoretical prediction and experimental observation) of a large-gap topological-insulator class with spin-polarized single-Dirac-cone on the surface (2009, background): “The strong-topological-insulator phase contains surface states (SSs) with novel electromagnetic properties [7, 8, 9, 10, 11, 12, 13, 14, 15].”