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Research Article

Large valley-polarized state in single-layer NbX2 (X = S, Se): Theoretical prediction

Yanmei Zang, Yandong Ma( ), Rui Peng, Hao Wang, Baibiao Huang, Ying Dai( )
School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Shandanan Street 27, Jinan 250100, China
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Abstract

Exploring two-dimensional valleytronic crystals with large valley-polarized state is of considerable importance due to the promising applications in next-generation information related devices. Here, we show first-principles evidence that single-layer NbX2 (X = S, Se) is potentially the long-sought two-dimensional valleytronic crystal. Specifically, the valley-polarized state is found to occur spontaneously in single-layer NbX2, without needing any external tuning, which arises from their intrinsic magnetic exchange interaction and inversion asymmetry. Moreover, the strong spin-orbit coupling strength within Nb-d orbitals renders their valley- polarized states being of remarkably large (NbS2 ~ 156 meV/NbSe2 ~ 219 meV), enabling practical utilization of their valley physics accessible. In additional, it is predicted that the valley physics (i.e., anomalous valley Hall effect) in single-layer NbX2 is switchable via applying moderate strain. These findings make single-layer NbX2 tantalizing candidates for realizing high-performance and controllable valleytronic devices.

Keywords

valley polarizationferromagneticanomalous valley Hall effectNbX2 (X = S, Se)first-principles

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References

[1]
D. Xiao,; W. Yao,; Q. Niu, Valley-contrasting physics in graphene: Magnetic moment and topological transport. Phys. Rev. Lett. 2007, 99, 236809.
Crossref Google Scholar
[2]
W. Yao,; D. Xiao,; Q. Niu, Valley-dependent optoelectronics from inversion symmetry breaking. Phys. Rev. B 2008, 77, 235406.
Crossref Google Scholar
[3]
F. Zhang,; J. Jung,; G. A. Fiete,; Q. Niu,; A. H. MacDonald, Spontaneous quantum Hall states in chirally stacked few-layer graphene systems. Phys. Rev. Lett. 2011, 106, 156801.
Crossref Google Scholar
[4]
Y. D. Ma,; L. Z. Kou,; A. J. Du,; B. B. Huang,; Y. Dai,; T. Heine, Conduction-band valley spin splitting in single-layer H-Tl2O. Phys. Rev. B 2018, 97, 035444.
Google Scholar
[5]
D. Xiao,; G. B. Liu,; W. X. Feng,; X. D. Xu,; W. Yao, Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides. Phys. Rev. Lett. 2012, 108, 196802.
Crossref Google Scholar
[6]
C. A. Lei,; Y. D. Ma,; T. Zhang,; X. L. Xu,; B. B. Huang,; Y. Dai, Valley polarization in monolayer CrX2 (X = S, Se) with magnetically doping and proximity coupling. New J. Phys. 2020, 22, 033002.
Crossref Google Scholar
[7]
J. R. Schaibley,; H. Y. Yu,; G. Clark,; P. Rivera,; J. S. Ross,; K. L. Seyler,; W. Yao,; X. D. Xu, Valleytronics in 2D materials. Nat. Rev. Mater. 2016, 1, 16055.
Crossref Google Scholar
[8]
Q. Pei,; B. Z. Zhou,; W. B. Mi,; C. Y. Cheng, Triferroic material and electrical control of valley degree of freedom. ACS Appl. Mater. Interfaces 2019, 11, 12675-12682
Crossref Google Scholar
[9]
H. L. Zeng,; J. F. Dai,; W. Yao,; D. Xiao,; X. D. Cui, Valley polarization in MoS2 monolayers by optical pumping. Nat. Nanotechnol. 2012, 7, 490-493.
Crossref Google Scholar
[10]
T. Cao,; G. Wang,; W. P. Han,; H. Q. Ye,; C. R. Zhu,; J. R. Shi,; Q. Niu,; P. H. Tan,; E. G. Wang,; B. L.; Liu, et al. Valley-selective circular dichroism of monolayer molybdenum disulphide. Nat. Commun. 2012, 3, 887.
Crossref Google Scholar
[11]
P. Zhao,; Y. D. Ma,; C. A. Lei,; H. Wang,; B. B. Huang,; Y. Dai, Single-layer LaBr2: Two-dimensional valleytronic semiconductor with spontaneous spin and valley polarizations. Appl. Phys. Lett. 2019, 115, 261605.
Crossref Google Scholar
[12]
K. F. Mak,; K. L. He,; J. Shan,; T. F. Heinz, Control of valley polarization in monolayer MoS2 by optical helicity. Nat. Nanotechnol. 2012, 7, 494-498.
Crossref Google Scholar
[13]
N. Singh,; U. Schwingenschlogl, A route to permanent valley polarization in monolayer MoS2. Adv. Mater. 2017, 29, 1600970.
Crossref Google Scholar
[14]
X. L. Xu,; Y. D. Ma,; T. Zhang,; C. A. Lei,; B. B. Huang,; Y. Dai, Nonmetal-atom-doping-induced valley polarization in single-layer Tl2O. J. Phys. Chem. Lett. 2019, 10, 4535-4541.
Crossref Google Scholar
[15]
Q. Y. Zhang,; S. A. Yang,; W. B. Mi,; Y. C. Cheng,; U. Schwingenschlögl, Large spin-valley polarization in monolayer MoTe2 on top of EuO(111). Adv. Mater. 2016, 28, 959-966.
Crossref Google Scholar
[16]
N. B. Li,; J. Y. Zhang,; Y. Xue,; T. Zhou,; Z. Q. Yang, Large valley polarization in monolayer MoTe2 on a magnetic substrate. Phys. Chem. Chem. Phys. 2018, 20, 3805-3812.
Crossref Google Scholar
[17]
J. S. Qi,; X. Li,; Q. Niu,; J. Feng, Giant and tunable valley degeneracy splitting in MoTe2. Phys. Rev. B 2015, 92, 121403.
Google Scholar
[18]
X. F. Ma,; L. Yin,; J. J. Zou,; W. B. Mi,; X. C. Wang, Strain-tailored valley polarization and magnetic anisotropy in two-dimensional 2H-VS2/Cr2C heterostructures. J. Phys. Chem. C 2019, 123, 17440-17448.
Crossref Google Scholar
[19]
R. Peng,; Y. D. Ma,; S. Zhang,; B. B. Huang,; Y. Dai, Valley polarization in Janus single-layer MoSSe via magnetic doping. J. Phys. Chem. Lett. 2018, 9, 3612-3617.
Crossref Google Scholar
[20]
T. C. Berkelbach,; M. S. Hybertsen,; D. R. Reichman, Theory of neutral and charged excitons in monolayer transition metal dichalcogenides. Phys. Rev. B 2013, 88, 045318.
Crossref Google Scholar
[21]
H. Z. Lu,; W. Yao,; D. Xiao,; S. Q. Shen, Intervalley scattering and localization behaviors of spin-valley coupled Dirac fermions. Phys. Rev. Lett. 2013, 110, 016806.
Crossref Google Scholar
[22]
O. L. Sanchez,; D. Ovchinnikov,; S. Misra,; A. Allain,; A. Kis, Valley polarization by spin injection in a light-emitting van der Waals heterojunction. Nano Lett. 2016, 16, 5792-5797.
Crossref Google Scholar
[23]
C. M. Zhang,; Y. H. Nie,; S. Sanvito,; A. J. Du, First-principles prediction of a room-temperature ferromagnetic Janus VSSe monolayer with piezoelectricity, ferroelasticity, and large valley polarization. Nano Lett. 2019, 19, 1366-1370.
Crossref Google Scholar
[24]
L. Z. Kou,; S. C. Wu,; C. Felser,; T. Frauenheim,; C. F. Chen,; B. H. Yan, Robust 2D topological insulators in van der Waals heterostructures. ACS Nano 2014, 8, 10448-10454.
Crossref Google Scholar
[25]
L. Z. Kou,; B. H. Yan,; F. M. Hu,; S. C. Wu,; T. O. Wehling,; C. Felser,; C. F. Chen,; T. Frauenheim, Graphene-based topological insulator with an intrinsic bulk band gap above room temperature. Nano Lett. 2013, 13, 6251-6255.
Crossref Google Scholar
[26]
L. Z. Kou,; F. M. Hu,; B. H. Yan,; T. Wehling,; C. Felser,; T. Frauenheim,; C. F. Chen, Proximity enhanced quantum spin Hall state in graphene. Carbon 2015, 87, 418-423.
Crossref Google Scholar
[27]
D. MacNeill,; C. Heikes,; K. F. Mak,; Z. Anderson,; A. Kormányos,; V. Zólyomi,; J. Park,; D. C. Ralph, Breaking of valley degeneracy by magnetic field in monolayer MoSe2. Phys. Rev. Lett. 2015, 114, 037401.
Crossref Google Scholar
[28]
Y. L. Li,; J. Ludwig,; T. Low,; A. Chernikov,; X. Cui,; G. Arefe,; Y. D. Kim,; A. M. Van Der Zande,; A. Rigosi,; H. M. Hill, et al. Valley splitting and polarization by the Zeeman effect in monolayer MoSe2. Phys. Rev. Lett. 2014, 113, 266804.
Crossref Google Scholar
[29]
Y. J. Wu,; C. Shen,; Q. H. Tan,; J. Shi,; X. F. Liu,; Z. H. Wu,; J. Zhang,; P. H. Tan,; H. Z. Zheng, Valley Zeeman splitting of monolayer MoS2 probed by low-field magnetic circular dichroism spectroscopy at room temperature. Appl. Phys. Lett. 2018, 112, 153105.
Crossref Google Scholar
[30]
B. Huang,; G. Clark,; E. Navarro-Moratalla,; D. R. Klein,; R. Cheng,; K. L. Seyler,; D. Zhong,; E. Schmidgall,; M. A. Mcguire,; D. H. Cobden, et al. Layer-dependent ferromagnetism in a van der Waals crystal down to the monolayer limit. Nature 2017, 546, 270-273.
Crossref Google Scholar
[31]
C. Gong,; L. Li,; Z. L. Li,; H. W. Ji,; A. Stern,; Y. Xia,; T. Cao,; W. Bao,; C. Z. Wang,; Y. Wang, et al. Discovery of intrinsic ferromagnetism in two-dimensional van der Waals crystals. Nature 2017, 546, 265-269.
Crossref Google Scholar
[32]
C. X. Huang,; J. S. Feng,; F. Wu,; D. Ahmed,; B. Huang,; H. J. Xiang,; K. M. Deng,; E. Kan, Toward intrinsic room-temperature ferromagnetism in two-dimensional semiconductors. J. Am. Chem. Soc. 2018, 140, 11519-11525.
Crossref Google Scholar
[33]
N. H. Miao,; B. Xu,; L. G. Zhu,; J. Zhou,; Z. M. Sun, 2D intrinsic ferromagnets from van der Waals antiferromagnets. J. Am. Chem. Soc. 2018, 140, 2417-2420.
Crossref Google Scholar
[34]
C. X. Huang,; Y. P. Du,; H. P. Wu,; H. J. Xiang,; K. M. Deng,; E. Kan, Prediction of intrinsic ferromagnetic ferroelectricity in a transition-metal halide monolayer. Phys. Rev. Lett. 2018, 120, 147601.
Crossref Google Scholar
[35]
P. H. Jiang,; C. Wang,; D. C. Chen,; Z. C. Zhong,; Z. Yuan,; Z. Y. Lu,; W. Ji, Stacking tunable interlayer magnetism in bilayer CrI3. Phys. Rev. B 2019, 99, 144401.
Crossref Google Scholar
[36]
W. Y. Tong,; S. J. Gong,; X. G. Wan,; C. G. Duan, Concepts of ferrovalley material and anomalous valley Hall effect. Nat. Commun. 2016, 7, 13612.
Crossref Google Scholar
[37]
P. Zhao,; Y. D. Ma,; H. Wang,; B. B. Huang,; L. Z. Kou,; Y. Dai, Intrinsic valley polarization and anomalous valley Hall effect in single-layer 2H-FeCl2. arXiv: 2003.04561, 2020.
[38]
R. Peng,; Y. D. Ma,; X. L. Xu,; Z. L. He,; B. B. Huang,; Y. Dai, Intrinsic anomalous valley Hall effect in single-layer Nb3I8. Phys. Rev. B 2020, 102, 035412.
Crossref Google Scholar
[39]
W. W. Zhao,; B. H. Dong,; Z. L. Guo,; G. Su,; R. J. Gao,; W. Wang,; L. X. Cao, Colloidal synthesis of VSe2 single-layer nanosheets as novel electrocatalysts for the hydrogen evolution reaction. Chem. Commun. 2016, 52, 9228-9231.
Crossref Google Scholar
[40]
K. Krämer,; T. Schleid,; M. Schulze,; W. Urland,; G. Meyer, Three bromides of lanthanum: LaBr2, La2Br5, and LaBr3. Z. Anorg. Allg. Chem. 1989, 575, 61-70.
Crossref Google Scholar
[41]
N. J. Doran,; D. J. Titterington,; B. Ricco,; G. Wexler, A tight binding fit to the bandstructure of 2H-NbSe2 and NbS2. J. Phys. C: Solid State Phys. 1978, 11, 685.
Crossref Google Scholar
[42]
H. Wang,; X. W. Huang,; J. H. Lin,; J. Cui,; Y. Chen,; C. Zhu,; F. C. Liu,; Q. S. Zeng,; J. D. Zhou,; P. Yu, et al. High-quality monolayer superconductor NbSe2 grown by chemical vapour deposition. Nat. Commun. 2017, 8, 394.
Crossref Google Scholar
[43]
X. J. Zhu,; Y. Q. Guo,; H. Cheng,; J. Dai,; X. D. An,; J. Y. Zhao,; K. Z. Tian,; S. Q. Wei,; X. C. Zeng,; C. Z. Wu, et al. Signature of coexistence of superconductivity and ferromagnetism in two- dimensional NbSe2 triggered by surface molecular adsorption. Nat. Commun. 2016, 7, 11210.
Crossref Google Scholar
[44]
C. S. Lian,; C. Si,; W. H. Duan, Unveiling charge-density wave, superconductivity, and their competitive nature in two-dimensional NbSe2 Nano Lett. 2018, 18, 2924-2929.
Crossref Google Scholar
[45]
R. Yan,; G. Khalsa,; B. T. Schaefer,; A. Jarjour,; S. Rouvimov,; K. C. Nowack,; H. G. Xing,; D. Jena, Thickness dependence of superconductivity in ultrathin NbS2 Appl. Phys. Express 2019, 12, 023008.
Crossref Google Scholar
[46]
S. H. Zhao,; T. Hotta,; T. Koretsune,; K. Watanabe,; T. Taniguchi,; K. Sugawara, T. Takahashi,; H. Shinohara,; R. Kitaura, Two-dimensional metallic NbS2: Growth, optical identification and transport properties. 2D Mater. 2016, 3, 025027.
Crossref Google Scholar
[47]
Y. D. Ma,; A. Kuc,; Y. Jing,; P. Philipsen,; T. Heine, Two-dimensional haeckelite NbS2: A diamagnetic high-mobility semiconductor with Nb4+ ions. Angew. Chem., Int. Ed. 2017, 56, 10214-10218.
Crossref Google Scholar
[48]
Y. Xu,; X. F. Liu,; W. L. Guo, Tensile strain induced switching of magnetic states in NbSe2 and NbS2 single layers. Nanoscale 2014, 6, 12929-12933.
Crossref Google Scholar
[49]
Y. J. Sun,; Z. W. Zhuo,; X. J. Wu, Bipolar magnetism in a two-dimensional NbS2 semiconductor with high curie temperature. J. Mater. Chem. C 2018, 6, 11401-11406.
Crossref Google Scholar
[50]
Y. G. Zhou,; Z. G. Wang,; P. Yang,; X. T. Zu,; L. Yang,; X. Sun,; F. Gao, Tensile strain switched ferromagnetism in layered NbS2 and NbSe2 ACS Nano 2012, 6, 9727-9736.
Crossref Google Scholar
[51]
Y. Wang,; M. Qiao,; Y. F. Li,; Z. F. Chen, A two-dimensional CaSi monolayer with quasi-planar pentacoordinate silicon. Nanoscale Horiz. 2018, 3, 327-334.
Crossref Google Scholar
[52]
R. Peng,; Y. D. Ma,; B. B. Huang,; Y. Dai, Two-dimensional Janus PtSSe for photocatalytic water splitting under the visible or infrared light. J. Mater. Chem. A 2019, 7, 603-610.
Crossref Google Scholar
[53]
Y. Ding,; Y. L. Wang, Density functional theory study of the silicene-like SiX and XSi3 (X = B, C, N, Al, P) honeycomb lattices: The various buckled structures and versatile electronic properties. J. Phys. Chem. C 2013, 117, 18266-18278.
Crossref Google Scholar
[54]
E. Cadelano,; P. L. Palla,; S. Giordano,; L. Colombo, Elastic properties of hydrogenated graphene. Phys. Rev. B 2010, 82, 235414.
Crossref Google Scholar
[55]
R. Peng,; Y. D. Ma,; Z. L. He,; B. B. Huang,; L. Z. Kou,; Y. Dai, Single-layer Ag2S: A two-dimensional bidirectional auxetic semiconductor. Nano Lett. 2019, 19, 1227-1233.
Crossref Google Scholar
[56]
R. C. Andrew,; R. E. Mapasha,; A. M. Ukpong,; N. Chetty, Mechanical properties of graphene and boronitrene. Phys. Rev. B 2012, 85, 125428.
Crossref Google Scholar
[57]
K. H. Michel,; B. Verberck, Theory of elastic and piezoelectric effects in two-dimensional hexagonal boron nitride. Phys. Rev. B 2009, 80, 224301.
Crossref Google Scholar
[58]
Z. B. Gao,; X. Dong,; N. B. Li,; J. Ren, Novel two-dimensional silicon dioxide with in-plane negative Poisson’s ratio. Nano Lett. 2017, 17, 772-777.
Crossref Google Scholar
[59]
C. Gong,; H. J. Zhang,; W. H. Wang,; L. Colombo,; R. M. Wallace,; K. Cho, Band alignment of two-dimensional transition metal dichalcogenides: Application in tunnel field effect transistors. Appl. Phys. Lett. 2013, 103, 053513.
Crossref Google Scholar
[60]
D. J. Thouless,; M. Kohmoto,; M. P. Nightingale,; M. den Nijs, Quantized Hall conductance in a two-dimensional periodic potential. Phys. Rev. Lett. 1982, 49, 405-408.
Crossref Google Scholar
[61]
G. Kresse,; J. Furthmüller, Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. Phys. Rev. B 1996, 54, 11169-11186.
Crossref Google Scholar
[62]
G. Kresse,; J. Furthmüller, Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set. Comput. Mater. Sci. 1996, 6, 15-50.
Crossref Google Scholar
[63]
H. J Monkhorst,; J. D. Pack, Special points for Brillouin-zone integrations. Phys. Rev. B 1976, 13, 5188-5192.
Crossref Google Scholar
[64]
J. P. Perdew,; K. Burke,; M. Ernzerhof, Generalized gradient approximation made simple. Phys. Rev. Lett. 1996, 77, 3865.
Crossref Google Scholar
[65]
G. Kresse,; D. Joubert, From ultrasoft pseudopotentials to the projector augmented-wave method. Phys. Rev. B 1999, 59, 1758-1775.
Crossref Google Scholar
[66]
J. Heyd,; G. E. Scuseria,; M. Ernzerhof, Hybrid functionals based on a screened Coulomb potential. J. Chem. Phys. 2003, 118, 8207-8215.
Crossref Google Scholar
[67]
A. Togo,; F. Oba,; I. Tanaka, First-principles calculations of the ferroelastic transition between rutile-type and CaCl2-type SiO2 at high pressures. Phys. Rev. B 2008, 78, 134106.
Crossref Google Scholar
[68]
A. A. Mostofi,; J. R. Yates,; Y. S. Lee,; I. Souza,; D. Vanderbilt,; N. Marzari, wannier90: A tool for obtaining maximally-localised Wannier functions. Comput. Phys. Commun. 2008, 178, 685-699.
Crossref Google Scholar
Nano Research
Volume 14 Issue 3,
March 2021
Pages 834-839
DOI: 10.1007/s12274-020-3121-1
Cite this article:
Zang Y, Ma Y, Peng R, et al. Large valley-polarized state in single-layer NbX2 (X = S, Se): Theoretical prediction. Nano Research, 2021, 14(3): 834-839. https://doi.org/10.1007/s12274-020-3121-1
Topics:
CrystalsNiobium compoundsSelenium compoundsSpin orbit couplingVanadium compounds

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Received: 16 July 2020
Revised: 24 August 2020
Accepted: 15 September 2020
Published: 01 March 2021
© Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020
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