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Title: Topological Phases in Graphene Nanoribbons: Junction States, Spin Centers, and Quantum Spin Chains

Abstract

We show that semiconducting graphene nanoribbons (GNRs) of different width, edge, and end termination (synthesizable from molecular precursors with atomic precision) belong to different electronic topological classes. The topological phase of GNRs is protected by spatial symmetries and dictated by the terminating unit cell. We have derived explicit formulas for their topological invariants and shown that localized junction states developed between two GNRs of distinct topology may be tuned by lateral junction geometry. The topology of a GNR can be further modified by dopants, such as a periodic array of boron atoms. In a superlattice consisting of segments of doped and pristine GNRs, the junction states are stable spin centers, forming a Heisenberg antiferromagnetic spin 1/2 chain with tunable exchange interaction. Furthermore, the discoveries here not only are of scientific interest for studies of quasi-one-dimensional systems, but also open a new path for design principles of future GNR-based devices through their topological characters.

Authors:
 [1];  [1];  [1]
  1. Univ. of California, Berkeley, CA (United States). Dept. of Physics; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Materials Sciences Division
Publication Date:
Research Org.:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1544373
Alternate Identifier(s):
OSTI ID: 1375501
Grant/Contract Number:  
AC02-05CH11231
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review Letters
Additional Journal Information:
Journal Volume: 119; Journal Issue: 7; Journal ID: ISSN 0031-9007
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English

Citation Formats

Cao, Ting, Zhao, Fangzhou, and Louie, Steven G. Topological Phases in Graphene Nanoribbons: Junction States, Spin Centers, and Quantum Spin Chains. United States: N. p., 2017. Web. doi:10.1103/PhysRevLett.119.076401.
Cao, Ting, Zhao, Fangzhou, & Louie, Steven G. Topological Phases in Graphene Nanoribbons: Junction States, Spin Centers, and Quantum Spin Chains. United States. doi:10.1103/PhysRevLett.119.076401.
Cao, Ting, Zhao, Fangzhou, and Louie, Steven G. Wed . "Topological Phases in Graphene Nanoribbons: Junction States, Spin Centers, and Quantum Spin Chains". United States. doi:10.1103/PhysRevLett.119.076401. https://www.osti.gov/servlets/purl/1544373.
@article{osti_1544373,
title = {Topological Phases in Graphene Nanoribbons: Junction States, Spin Centers, and Quantum Spin Chains},
author = {Cao, Ting and Zhao, Fangzhou and Louie, Steven G.},
abstractNote = {We show that semiconducting graphene nanoribbons (GNRs) of different width, edge, and end termination (synthesizable from molecular precursors with atomic precision) belong to different electronic topological classes. The topological phase of GNRs is protected by spatial symmetries and dictated by the terminating unit cell. We have derived explicit formulas for their topological invariants and shown that localized junction states developed between two GNRs of distinct topology may be tuned by lateral junction geometry. The topology of a GNR can be further modified by dopants, such as a periodic array of boron atoms. In a superlattice consisting of segments of doped and pristine GNRs, the junction states are stable spin centers, forming a Heisenberg antiferromagnetic spin 1/2 chain with tunable exchange interaction. Furthermore, the discoveries here not only are of scientific interest for studies of quasi-one-dimensional systems, but also open a new path for design principles of future GNR-based devices through their topological characters.},
doi = {10.1103/PhysRevLett.119.076401},
journal = {Physical Review Letters},
number = 7,
volume = 119,
place = {United States},
year = {2017},
month = {8}
}

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Cited by: 18 works
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Works referenced in this record:

QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials
journal, September 2009

  • Giannozzi, Paolo; Baroni, Stefano; Bonini, Nicola
  • Journal of Physics: Condensed Matter, Vol. 21, Issue 39, Article No. 395502
  • DOI: 10.1088/0953-8984/21/39/395502

Colloquium: Topological insulators
journal, November 2010


Electron correlation in semiconductors and insulators: Band gaps and quasiparticle energies
journal, October 1986


Ordering, metastability and phase transitions in two-dimensional systems
journal, April 1973

  • Kosterlitz, J M; Thouless, D J
  • Journal of Physics C: Solid State Physics, Vol. 6, Issue 7, p. 1181-1203
  • DOI: 10.1088/0022-3719/6/7/010