Directional massless Dirac fermions in a layered van der Waals material with one-dimensional long-range order
Source abstract
Abstract
One or a few layers of van der Waals (vdW) materials are promising for applications in nanoscale electronics. Established properties include high mobility in graphene, a large direct gap in monolayer MoS2, the quantum spin Hall effect in monolayer WTe2 and so on. These exciting properties arise from electron quantum confinement in the two-dimensional limit. Here, we use angle-resolved photoemission spectroscopy to reveal directional massless Dirac fermions due to one-dimensional confinement of carriers in the layered vdW material NbSi0.45Te2. The one-dimensional directional massless Dirac fermions are protected by non-symmorphic symmetry, and emerge from a stripe-like structural modulation with long-range translational symmetry only along the stripe direction as we show using scanning tunnelling microscopy. Our work not only provides a playground for investigating further the properties of directional massless Dirac fermions, but also introduces a unique component with one-dimensional long-range order for engineering nano-electronic devices based on heterostructures of vdW materials.
Source: europepmc · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Topological Materials and Phenomena · 2D Materials and Applications · Graphene research and applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (42)
Show source-provided references
1. Novoselov, K. S. et al. Electric field effect in atomically thin carbon films. Science 306, 666–669 (2004).10.1126/science.1102896 ↗
2. Mak, K. F., Lee, C., Hone, J., Shan, J. & Heinz, T. F. Atomically thin MoS2: a new direct-gap semiconductor. Phys. Rev. Lett. 105, 136805 (2010).10.1103/PhysRevLett.105.136805 ↗
3. Lu, J. M. et al. Evidence for two-dimensional Ising superconductivity in gated MoS2. Science 350, 1353–1357 (2015).10.1126/science.aab2277 ↗
4. Xi, X. X. et al. Ising pairing in superconducting NbSe2 atomic layers. Nat. Phys. 12, 139–143 (2016).10.1038/nphys3538 ↗
5. Qian, X. F., Liu, J. W., Fu, L. & Li, J. Quantum spin Hall effect in two-dimensional transition metal dichalcogenides. Science 346, 1344–1347 (2014).10.1126/science.1256815 ↗
6. Fei, Z. Y. et al. Edge conduction in monolayer WTe2. Nat. Phys. 13, 677–682 (2017).10.1038/nphys4091 ↗
7. Tang, S. J. et al. Quantum spin hall state in monolayer 1T’-WTe2. Nat. Phys. 13, 683–687 (2017).10.1038/nphys4174 ↗
8. Wu, S. F. et al. Observation of the quantum spin hall effect up to 100 kelvin in a monolayer crystal. Science 359, 76–79 (2018).10.1126/science.aan6003 ↗
9. Zhu, Z. et al. Quasiparticle interference and nonsymmorphic effect on a floating band surface state of ZrSiSe. Nat. Commum. 9, 4153 (2018).10.1038/s41467-018-06661-9 ↗
10. Gong, C. et al. Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals. Nature 546, 265–269 (2017).10.1038/nature22060 ↗
11. Huang, B. et al. Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit. Nature 546, 270–273 (2017).10.1038/nature22391 ↗
12. Cao, Y. et al. Unconventional superconductivity in magic-angle graphene superlattices. Nature 556, 43–50 (2018).10.1038/nature26160 ↗
13. Cao, Y. et al. Correlated insulator behaviour at half-filling in magic angle graphene superlattices. Nature 556, 80–84 (2018).10.1038/nature26154 ↗
14. Young, S. M. & Kane, C. L. Dirac semimetals in two dimensions. Phys. Rev. Lett. 115, 126803 (2015).10.1103/PhysRevLett.115.126803 ↗
15. Bzdušek, T., Wu, Q., Rüegg, A., Sigrist, M. & Soluyanov, A. A. Nodal-chain metals. Nature 538, 75–78 (2016).10.1038/nature19099 ↗
16. Wang, Z. et al. Dirac semimetal and topological phase transitions in A3Bi (A = Na, K, Rb). Phys. Rev. B 85, 195320 (2012).10.1103/PhysRevB.85.195320 ↗
17. Li, J., Badding, M. E. & DiSalvo, F. J. New layered ternary niobium tellurides: synthesis, structure, and properties of niobium metal telluride. NbMTe2 (M = iron, cobalt). Inorg. Chem. 31, 1050–1054 (1992).10.1021/ic00032a024 ↗
18. Huang, B., Shang, B. & Huang, J. Crystal structure of mixed metal cluster Co2Nb2Te4 obtained by solid state reaction. Jiegou Huaxue (J. Struct. Chem.) 7, 133 (1988).
19. Huang, B., Shang, B. & Huang, J. Crystal structure of mixed metal cluster Ni2Nb2Te4 obtained by solid state reaction. Jiegou Huaxue (J. Struct. Chem.) 7, 214 (1988).
20. Huang, B., Shang, B. & Huang, J. Synthesis and crystal structure of a new ternary tantalum chalcogenide Ni2Ta2Te4. Jiegou Huaxue (J. Struct. Chem.) 8, 145 (1989).
21. Li, J., Badding, M. E. & DiSalvo, F. J. Synthesis and structure of Nb3SiTe6, a new layered ternary niobium telluride compound. J. Alloy. Compd. 184, 257–163 (1992).10.1016/0925-8388(92)90499-Y ↗
22. Hu, J. et al. Enhanced electron coherence in atomically thin Nb3SiTe6. Nat. Phys. 11, 471–476 (2015).10.1038/nphys3321 ↗
23. Li, Si et al. Nonsymmorphic-symmetry-protected hourglass dirac loop, nodal line, and dirac point in bulk and monolayer X3SiTe6 (X = Ta, Nb). Phys. Rev. B 97, 045131 (2018).10.1103/PhysRevB.97.045131 ↗
24. Boucher, F., Zhukov, V. & Evain, M. MAxTe2 phases (M = Nb, Ta; A = Si, Ge; 1/3 ≤ x ≤ 1/2): an electronic band structure calculation analysis. Chem. 35, 7649–7654 (1996).
25. Weber, F. et al. Three-dimensional Fermi surface of 2H-NbSe2: implications for the mechanism of charge density waves. Phys. Rev. B 97, 235122 (2018).10.1103/PhysRevB.97.235122 ↗
26. Sato, T. et al. Observation of band crossings protected by nonsymmorphic symmetry in the layered ternary telluride Ta3SiTe6. Phys. Rev. B 98, 121111(R) (2018).10.1103/PhysRevB.98.121111 ↗
27. Riley, J. M. et al. Direct observation of spin-polarized bulk bands in an inversion-symmetric semiconductor. Nat. Phys. 10, 835–839 (2014).10.1038/nphys3105 ↗
28. Pescia, D., Law, A. R., Johnson, M. T. & Hughes, H. P. Determination of observable conduction band symmetry in angle-resolved electron spectroscopies: Non-symmorphic space groups. Solid State Commun. 56, 809–812 (1985).10.1016/0038-1098(85)90314-X ↗
29. Finteis, Th et al. Occupied and unoccupied electronic band structure of WSe2. Phys. Rev. B 55, 10400 (1997).10.1103/PhysRevB.55.10400 ↗
30. Landolt, G. et al. Bulk and surface rashba splitting in single termination BiTeCl. New J. Phys. 15, 085022 (2013).10.1088/1367-2630/15/8/085022 ↗
31. Koller, G. et al. Intra- and intermolecular band dispersion in an organic crystal. Science 317, 351–355 (2007).10.1126/science.1143239 ↗
32. Yin, D., Chen, C., Saito, M., Inoue, K. & Ikuhara, Y. Ceramic phases with one-dimensional long-range order. Nat. Mater. 18, 19–23 (2019).10.1038/s41563-018-0240-0 ↗
33. Liu, Z. K. et al. Discovery of a three-dimensional topological dirac semimetal, Na3Bi. Science 343, 864–867 (2014).10.1126/science.1245085 ↗
34. Neupane, M. et al. Observation of a three-dimensional topological dirac semimetal phase in high-mobility Cd3As2. Nat. Commun. 5, 3786 (2014).10.1038/ncomms4786 ↗
35. Borisenko, S. et al. Experimental realization of a three-dimensional dirac semimetal. Phys. Rev. Lett. 113, 027603 (2014).10.1103/PhysRevLett.113.027603 ↗
36. Schoop, L. M. et al. Dirac cone protected by non-symmorphic symmetry and three-dimensional dirac line node in ZrSiS. Nat. Commun. 7, 11696 (2016).10.1038/ncomms11696 ↗
37. Ekahana, S. A. et al. Observation of nodal line in non-symmorphic topological semimetal InBi. New J. Phys. 19, 065007 (2017).10.1088/1367-2630/aa75a1 ↗
38. Schoop, L. M. et al. Tunable weyl and dirac states in the nonsymmorphic compound CeSbTe. Sci. Adv. 4, eaar2317 (2018).10.1126/sciadv.aar2317 ↗
39. Nakayama, K. et al. Band splitting and weyl nodes in trigonal tellurium studied by angle-resolved photoemission spectroscopy and density functional theory. Phys. Rev. B 95, 125204 (2017).10.1103/PhysRevB.95.125204 ↗
40. Weng, H. et al. Topological node-line semimetal in three-dimensional graphene networks. Phys. Rev. B 92, 045108 (2015).10.1103/PhysRevB.92.045108 ↗
41. Bian, G. et al. Topological nodal-line fermions in spin-orbit metal PbTaSe2. Nat. Commun. 7, 10556 (2016).10.1038/ncomms10556 ↗
42. Hu, J. et al. Evidence of topological nodal-line fermions in ZrSiSe and ZrSiTe. Phys. Rev. Lett. 117, 016602 (2016).10.1103/PhysRevLett.117.016602 ↗