skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Experimental realization of two-dimensional Dirac nodal line fermions in monolayer Cu2Si

Abstract

Topological nodal line semimetals, a novel quantum state of materials, possess topologically nontrivial valence and conduction bands that touch at a line near the Fermi level. The exotic band structure can lead to various novel properties, such as long-range Coulomb interaction and flat Landau levels. Recently, topological nodal lines have been observed in several bulk materials, such as PtSn4, ZrSiS, TlTaSe2 and PbTaSe2. However, in two-dimensional materials, experimental research on nodal line fermions is still lacking. Here, we report the discovery of two-dimensional Dirac nodal line fermions in monolayer Cu2Si based on combined theoretical calculations and angle-resolved photoemission spectroscopy measurements. The Dirac nodal lines in Cu2Si form two concentric loops centred around the Γ point and are protected by mirror reflection symmetry. In conclusion, our results establish Cu2Si as a platform to study the novel physical properties in two-dimensional Dirac materials and provide opportunities to realize high-speed low-dissipation devices.

Authors:
ORCiD logo [1];  [2];  [3];  [3];  [4]; ORCiD logo [2];  [5]; ORCiD logo [6];  [7]; ORCiD logo [7]; ORCiD logo [7];  [6];  [3];  [8];  [6];  [6];  [6];  [4];  [4];  [2] more »;  [3] « less
  1. Univ. of Tokyo,Tokyo (Japan); Hiroshima Univ., Hiroshima (Japan)
  2. Beijing Inst. of Technology, Beijing (China)
  3. Univ. of Tokyo,Tokyo (Japan)
  4. Chinese Academy of Sciences (CAS), Beijing (China)
  5. Hiroshima Univ., Hiroshima (Japan); Chinese Academy of Sciences (CAS), Beijing (China)
  6. Hiroshima Univ., Hiroshima (Japan)
  7. Istituto di Struttura della Materia (ISM), Trieste (Italy)
  8. Univ. of Illinois, Chicago, IL (United States)
Publication Date:
Research Org.:
Univ. of Illinois, Chicago, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
OSTI Identifier:
1499693
Grant/Contract Number:  
FG02-07ER46383
Resource Type:
Accepted Manuscript
Journal Name:
Nature Communications
Additional Journal Information:
Journal Volume: 8; Journal Issue: 1; Journal ID: ISSN 2041-1723
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Feng, Baojie, Fu, Botao, Kasamatsu, Shusuke, Ito, Suguru, Cheng, Peng, Liu, Cheng-Cheng, Feng, Ya, Wu, Shilong, Mahatha, Sanjoy K., Sheverdyaeva, Polina, Moras, Paolo, Arita, Masashi, Sugino, Osamu, Chiang, Tai-Chang, Shimada, Kenya, Miyamoto, Koji, Okuda, Taichi, Wu, Kehui, Chen, Lan, Yao, Yugui, and Matsuda, Iwao. Experimental realization of two-dimensional Dirac nodal line fermions in monolayer Cu2Si. United States: N. p., 2017. Web. doi:10.1038/s41467-017-01108-z.
Feng, Baojie, Fu, Botao, Kasamatsu, Shusuke, Ito, Suguru, Cheng, Peng, Liu, Cheng-Cheng, Feng, Ya, Wu, Shilong, Mahatha, Sanjoy K., Sheverdyaeva, Polina, Moras, Paolo, Arita, Masashi, Sugino, Osamu, Chiang, Tai-Chang, Shimada, Kenya, Miyamoto, Koji, Okuda, Taichi, Wu, Kehui, Chen, Lan, Yao, Yugui, & Matsuda, Iwao. Experimental realization of two-dimensional Dirac nodal line fermions in monolayer Cu2Si. United States. doi:10.1038/s41467-017-01108-z.
Feng, Baojie, Fu, Botao, Kasamatsu, Shusuke, Ito, Suguru, Cheng, Peng, Liu, Cheng-Cheng, Feng, Ya, Wu, Shilong, Mahatha, Sanjoy K., Sheverdyaeva, Polina, Moras, Paolo, Arita, Masashi, Sugino, Osamu, Chiang, Tai-Chang, Shimada, Kenya, Miyamoto, Koji, Okuda, Taichi, Wu, Kehui, Chen, Lan, Yao, Yugui, and Matsuda, Iwao. Wed . "Experimental realization of two-dimensional Dirac nodal line fermions in monolayer Cu2Si". United States. doi:10.1038/s41467-017-01108-z. https://www.osti.gov/servlets/purl/1499693.
@article{osti_1499693,
title = {Experimental realization of two-dimensional Dirac nodal line fermions in monolayer Cu2Si},
author = {Feng, Baojie and Fu, Botao and Kasamatsu, Shusuke and Ito, Suguru and Cheng, Peng and Liu, Cheng-Cheng and Feng, Ya and Wu, Shilong and Mahatha, Sanjoy K. and Sheverdyaeva, Polina and Moras, Paolo and Arita, Masashi and Sugino, Osamu and Chiang, Tai-Chang and Shimada, Kenya and Miyamoto, Koji and Okuda, Taichi and Wu, Kehui and Chen, Lan and Yao, Yugui and Matsuda, Iwao},
abstractNote = {Topological nodal line semimetals, a novel quantum state of materials, possess topologically nontrivial valence and conduction bands that touch at a line near the Fermi level. The exotic band structure can lead to various novel properties, such as long-range Coulomb interaction and flat Landau levels. Recently, topological nodal lines have been observed in several bulk materials, such as PtSn4, ZrSiS, TlTaSe2 and PbTaSe2. However, in two-dimensional materials, experimental research on nodal line fermions is still lacking. Here, we report the discovery of two-dimensional Dirac nodal line fermions in monolayer Cu2Si based on combined theoretical calculations and angle-resolved photoemission spectroscopy measurements. The Dirac nodal lines in Cu2Si form two concentric loops centred around the Γ point and are protected by mirror reflection symmetry. In conclusion, our results establish Cu2Si as a platform to study the novel physical properties in two-dimensional Dirac materials and provide opportunities to realize high-speed low-dissipation devices.},
doi = {10.1038/s41467-017-01108-z},
journal = {Nature Communications},
number = 1,
volume = 8,
place = {United States},
year = {2017},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 65 works
Citation information provided by
Web of Science

Figures / Tables:

Fig. 1 Fig. 1 : Atomic and band structures of free-standing Cu2Si. a Top and side view. The orange and blue balls represent Cu and Si atoms, respectively. b, c Calculated band structures of Cu2Si without and with spin-orbit coupling (SOC), respectively. The vertical axis $E-E$$F$ corresponds to -$E$$B$, where $E$$B$ ismore » the binding energy. For simplicity, we label the three bands that cross the Fermi level $α$, $β$, and $γ$, respectively. The parity of mirror reflection symmetry for each band is labelled plus and minus signs in b. The zoom-in band structures in the blue and red ellipses are shown in g, h. d Band structure of Cu2Si after artificially increasing the intrinsic SOC by 20 times. e Fermi surface of Cu2Si without SOC. The blue, orange, and green lines correspond to bands $α, β$, and $γ$, respectively. f Momentum distribution of the nodal loops: NL1 (blue) and NL2 (orange). g, h Zoom-in band structures in the blue and red ellipses in c, which clearly show the SOC-induced gaps« less

Save / Share:

Works referenced in this record:

Topological nodal semimetals
journal, December 2011


Generalized Gradient Approximation Made Simple
journal, October 1996

  • Perdew, John P.; Burke, Kieron; Ernzerhof, Matthias
  • Physical Review Letters, Vol. 77, Issue 18, p. 3865-3868
  • DOI: 10.1103/PhysRevLett.77.3865

Topological insulators and superconductors
journal, October 2011


Atomic structure of the Cu/Si(111) interface by high-energy core-level Auger electron diffraction
journal, July 1985


A NIXSW structural investigation of the (√3×√3)R30°-Cu2Si surface alloy phase formed by SiH4 reaction with Cu(111)
journal, September 2001


Graphene-Like Two-Dimensional Materials
journal, January 2013

  • Xu, Mingsheng; Liang, Tao; Shi, Minmin
  • Chemical Reviews, Vol. 113, Issue 5, p. 3766-3798
  • DOI: 10.1021/cr300263a

Drumhead surface states and topological nodal-line fermions in TlTaSe 2
journal, March 2016


Two-Dimensional Cu 2 Si Monolayer with Planar Hexacoordinate Copper and Silicon Bonding
journal, February 2015

  • Yang, Li-Ming; Bačić, Vladimir; Popov, Ivan A.
  • Journal of the American Chemical Society, Vol. 137, Issue 7
  • DOI: 10.1021/ja513209c

Topological nodal-line fermions in spin-orbit metal PbTaSe2
journal, February 2016

  • Bian, Guang; Chang, Tay-Rong; Sankar, Raman
  • Nature Communications, Vol. 7, Issue 1
  • DOI: 10.1038/ncomms10556

Dirac node arcs in PtSn4
journal, April 2016

  • Wu, Yun; Wang, Lin-Lin; Mun, Eundeok
  • Nature Physics, Vol. 12, Issue 7
  • DOI: 10.1038/nphys3712

Methylsilane on Cu(111), a STM study of the R30°-Cu2Si surface silicide
journal, July 2005


Interaction of silane with Cu(111): Surface alloy and molecular chemisorbed phases
journal, April 1997


Dirac cone protected by non-symmorphic symmetry and three-dimensional Dirac line node in ZrSiS
journal, May 2016

  • Schoop, Leslie M.; Ali, Mazhar N.; Straßer, Carola
  • Nature Communications, Vol. 7, Issue 1
  • DOI: 10.1038/ncomms11696

Colloquium: Topological insulators
journal, November 2010


Observation of topological nodal fermion semimetal phase in ZrSiS
journal, May 2016


A simple tight-binding model of spin–orbit splitting of sp-derived surface states
journal, July 2000


Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996


Discovery of a Three-Dimensional Topological Dirac Semimetal, Na3Bi
journal, January 2014


Microscopic structure, discommensurations, and tiling of Si(111)/Cu-‘‘5×5’’
journal, July 1992


Two- and One-Dimensional Honeycomb Structures of Silicon and Germanium
journal, June 2009


The prediction of a family group of two-dimensional node-line semimetals
journal, January 2017

  • Jin, Yuan-Jun; Wang, Rui; Zhao, Jin-Zhu
  • Nanoscale, Vol. 9, Issue 35
  • DOI: 10.1039/C7NR03520A

Deduction of a three-phase model for the (√3×√3)R30°-Cu2Si/Cu(111) surface alloy
journal, November 2009


Discovery of a Weyl fermion semimetal and topological Fermi arcs
journal, July 2015


    Works referencing / citing this record:

    Perfect planar tetra-coordinated MC 6 monolayer: superior anode material for Li-ion battery
    journal, January 2019

    • Lu, Shaohua; Yang, Chuncheng; Fan, Dong
    • Physical Chemistry Chemical Physics, Vol. 21, Issue 27
    • DOI: 10.1039/c9cp01825e

    Dirac nodal lines protected against spin-orbit interaction in IrO 2
    journal, June 2019


    Perfect planar tetra-coordinated MC 6 monolayer: superior anode material for Li-ion battery
    journal, January 2019

    • Lu, Shaohua; Yang, Chuncheng; Fan, Dong
    • Physical Chemistry Chemical Physics, Vol. 21, Issue 27
    • DOI: 10.1039/c9cp01825e

    Dirac nodal lines protected against spin-orbit interaction in IrO 2
    journal, June 2019


      Figures/Tables have been extracted from DOE-funded journal article accepted manuscripts.