### Abstract

We report anisotropic Dirac-cone surface bands on a side-surface geometry of the topological insulator Bi_{2}Se_{3} revealed by first-principles density-functional calculations. We find that the electron velocity in the side-surface Dirac cone is anisotropically reduced from that in the (111)-surface Dirac cone, and the velocity is not in parallel with the wave vector k except for k in high-symmetry directions. The size of the electron spin depends on the direction of k due to anisotropic variation of the noncollinearity of the electron state. The anisotropy of electronic structures follows the corresponding anisotropy of the surface atomic structure. Low-energy effective Hamiltonian is proposed for side-surface Dirac fermions, and its implications are presented including refractive transport phenomena occurring at the edges of topological insulators where different surfaces meet.

Original language | English |
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Article number | 195425 |

Journal | Physical Review B - Condensed Matter and Materials Physics |

Volume | 84 |

Issue number | 19 |

DOIs | |

Publication status | Published - 2011 Nov 7 |

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### All Science Journal Classification (ASJC) codes

- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics

### Cite this

*Physical Review B - Condensed Matter and Materials Physics*,

*84*(19), [195425]. https://doi.org/10.1103/PhysRevB.84.195425

}

*Physical Review B - Condensed Matter and Materials Physics*, vol. 84, no. 19, 195425. https://doi.org/10.1103/PhysRevB.84.195425

**Low-velocity anisotropic Dirac fermions on the side surface of topological insulators.** / Moon, Chang Youn; Han, Jinhee; Lee, Hyungjun; Choi, Hyoung Joon.

Research output: Contribution to journal › Article

TY - JOUR

T1 - Low-velocity anisotropic Dirac fermions on the side surface of topological insulators

AU - Moon, Chang Youn

AU - Han, Jinhee

AU - Lee, Hyungjun

AU - Choi, Hyoung Joon

PY - 2011/11/7

Y1 - 2011/11/7

N2 - We report anisotropic Dirac-cone surface bands on a side-surface geometry of the topological insulator Bi2Se3 revealed by first-principles density-functional calculations. We find that the electron velocity in the side-surface Dirac cone is anisotropically reduced from that in the (111)-surface Dirac cone, and the velocity is not in parallel with the wave vector k except for k in high-symmetry directions. The size of the electron spin depends on the direction of k due to anisotropic variation of the noncollinearity of the electron state. The anisotropy of electronic structures follows the corresponding anisotropy of the surface atomic structure. Low-energy effective Hamiltonian is proposed for side-surface Dirac fermions, and its implications are presented including refractive transport phenomena occurring at the edges of topological insulators where different surfaces meet.

AB - We report anisotropic Dirac-cone surface bands on a side-surface geometry of the topological insulator Bi2Se3 revealed by first-principles density-functional calculations. We find that the electron velocity in the side-surface Dirac cone is anisotropically reduced from that in the (111)-surface Dirac cone, and the velocity is not in parallel with the wave vector k except for k in high-symmetry directions. The size of the electron spin depends on the direction of k due to anisotropic variation of the noncollinearity of the electron state. The anisotropy of electronic structures follows the corresponding anisotropy of the surface atomic structure. Low-energy effective Hamiltonian is proposed for side-surface Dirac fermions, and its implications are presented including refractive transport phenomena occurring at the edges of topological insulators where different surfaces meet.

UR - http://www.scopus.com/inward/record.url?scp=82655174071&partnerID=8YFLogxK

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U2 - 10.1103/PhysRevB.84.195425

DO - 10.1103/PhysRevB.84.195425

M3 - Article

AN - SCOPUS:82655174071

VL - 84

JO - Physical Review B-Condensed Matter

JF - Physical Review B-Condensed Matter

SN - 1098-0121

IS - 19

M1 - 195425

ER -