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Observation of pseudogap in SnSe2 atomic layers grown on graphite

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Abstract

Superconducting metal dichalcogenides (MDCs) present several similarities to the other layered superconductors like cuprates. The superconductivity in atomically thin MDCs has been demonstrated by recent experiments, however, the investigation of the superconductivity intertwined with other orders are scarce. Investigating the pseudogap in atomic layers of MDCs may help to understand the superconducting mechanism for these true two-dimensional (2D) superconducting systems. Herein we report a pseudogap opening in the tunneling spectra of thin layers of SnSe2 epitaxially grown on highly oriented pyrolytic graphite (HOPG) with scanning tunneling microscopy/spectroscopy (STM/STS). A significant V-shaped pseudogap was observed to open near the Fermi level (EF) in the STS. And at elevated temperatures, the gap gradually evolves to a shallow dip. Our experimental observations provide direct evidence of a pseudogap state in the electron-doped SnSe2 atomic layers on the HOPG surface, which may stimulate further exploration of the mechanism of superconductivity at 2D limit in MDCs.

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References

  1. K. S. Novoselov, A. Mishchenko, A. Carvalho, and A. H. Castro Neto, 2D materials and van der Waals heterostructures, Science 353(6298), 461 (2016)

    Article  Google Scholar 

  2. P. Chen, Y. H. Chan, X. Y. Fang, Y. Zhang, M. Y. Chou, S. K. Mo, Z. Hussain, A. V. Fedorov, and T. C. Chiang, Charge density wave transition in single-layer titanium diselenide, Nat. Commun. 6(1), 1 (2015)

    ADS  Google Scholar 

  3. P. Chen, W. W. Pai, Y. H. Chan, A. Takayama, C. Z. Xu, A. Karn, S. Hasegawa, M. Y. Chou, S. K. Mo, A. V. Fedorov, and T. C. Chiang, Emergence of charge density waves and a pseudogap in single-layer TiTe2, Nat. Commun. 8(1), 1 (2017)

    Article  Google Scholar 

  4. M. M. Ugeda, A. J. Bradley, Y. Zhang, S. Onishi, Y. Chen, W. Ruan, C. Ojeda-Aristizabal, H. Ryu, M. T. Edmonds, H. Z. Tsai, A. Riss, S. K. Mo, D. H. Lee, A. Zettl, Z. Hussain, Z. X. Shen, and M. F. Crommie, Characterization of collective ground states in single-layer NbSe2, Nat. Phys. 12(1), 92 (2016)

    Article  Google Scholar 

  5. X. X. Xi, Z. F. Wang, W. W. Zhao, J. H. Park, K. T. Law, H. Berger, L. Forró, J. Shan, and K. F. Mak, Ising pairing in superconducting NbSe2 atomic layers, Nat. Phys. 12(2), 139 (2016)

    Article  Google Scholar 

  6. Y. Cao, A. Mishchenko, G. L. Yu, E. Khestanova, A. P. Rooney, E. Prestat, A. V. Kretinin, P. Blake, M. B. Shalom, C. Woods, J. Chapman, G. Balakrishnan, I. V. Grigorieva, K. S. Novoselov, B. A. Piot, M. Potemski, K. Watanabe, T. Taniguchi, S. J. Haigh, A. K. Geim, and R. V. Gorbachev, Quality heterostructures from two-dimensional crystals unstable in air by their assembly in inert atmosphere, Nano Lett. 15(8), 4914 (2015)

    Article  ADS  Google Scholar 

  7. E. Navarro-Moratalla, J. O. Island, S. Mañas-Valero, E. Pinilla-Cienfuegos, A. Castellanos-Gomez, J. Quereda, G. Rubio-Bollinger, L. Chirolli, J. A. Silva-Guillén, N. Agraït, G. A. Steele, F. Guinéa, H. S. van der Zant, and E. Coronado, Enhanced superconductivity in atomically thin TaS2, Nat. Commun. 7(1), 1 (2016)

    Article  Google Scholar 

  8. J. T. Ye, Y. J. Zhang, R. Akashi, M. S. Bahramy, R. Arita, and Y. Iwasa, Superconducting dome in a gate-tuned band insulator, Science 338(6111), 1193 (2012)

    Article  ADS  Google Scholar 

  9. J. M. Lu, O. Zheliuk, I. Leermakers, N. F. Q. Yuan, U. Zeitler, K. T. Law, and J. T. Ye, Evidence for two-dimensional Ising superconductivity in gated MoS2, Science 350(6266), 1353 (2015)

    Article  MathSciNet  ADS  Google Scholar 

  10. Y. Saito, Y. Nakamura, M. S. Bahramy, Y. Kohama, J. T. Ye, Y. Kasahara, Y. Nakagawa, M. Onga, M. Tokunaga, T. Nojima, Y. Yanase, and Y. Iwasa, Superconductivity protected by spin-valley locking in ion-gated MoS2, Nat. Phys. 12(2), 144 (2016)

    Article  Google Scholar 

  11. C. Pépin, V. S. de Carvalho, T. Kloss, and X. Montiel, Pseudogap, charge order, and pairing density wave at the hot spots in cuprate superconductors, Phys. Rev. B. 90(19), 195207 (2014)

    Article  ADS  Google Scholar 

  12. T. Wu, H. Mayaffre, S. Krämer, M. Horvatić, C. Berthier, W. N. Hardy, R. X. Liang, D. A. Bonn, and M. H. Julien, Incipient charge order observed by NMR in the normal state of YBa2Cu3Oy, Nat. Commun. 6(1), 6438 (2014)

    Article  ADS  Google Scholar 

  13. J. J. Wen, H. Huang, S. J. Lee, H. Jang, J. Knight, Y. S. Lee, M. Fujita, K. M. Suzuki, S. Asano, S. A. Kivelson, C. C. Kao, and J. S. Lee, Observation of two types of charge-density-wave orders in superconducting La2−xSrxCuO4, Nat. Commun. 10(1), 3269 (2019)

    Article  ADS  Google Scholar 

  14. B. Loret, N. Auvray, Y. Gallais, M. Cazayous, A. Forget, D. Colson, M. H. Julien, I. Paul, M. Civelli, and A. Sacuto, Intimate link between charge density wave, pseudo-gap and superconducting energy scales in cuprates, Nat. Phys. 15(8), 15771 (2019)

    Article  Google Scholar 

  15. S. V. Borisenko, A. A. Kordyuk, A. N. Yaresko, V. B. Zabolotnyy, D. S. Inosov, R. Schuster, B. Büchner, R. Weber, R. Follath, L. Patthey, and H. Berger, Pseudogap and charge density waves in two dimensions, Phys. Rev. Lett. 100(19), 196402 (2008)

    Article  ADS  Google Scholar 

  16. D. V. Evtushinsky, A. A. Kordyuk, V. B. Zabolotnyy, D. S. Inosov, B. Büchner, H. Berger, L. Patthey, R. Follath, and S. V. Borisenko, Pseudogap-driven sign reversal of the Hall effect, Phys. Rev. Lett. 100(23), 236402 (2008)

    Article  ADS  Google Scholar 

  17. S. V. Borisenko, A. A. Kordyuk, V. B. Zabolotnyy, D. S. Inosov, D. Evtushinsky, B. Büchner, A. N. Yaresko, A. Varykhalov, R. Follath, W. Eberhardt, L. Patthey, and H. Berger, Two energy gaps and Fermi-surface “arcs” in NbSe2, Phys. Rev. Lett. 102(16), 166402 (2009)

    Article  ADS  Google Scholar 

  18. A. Soumyanarayanan, M. M. Yee, Y. He, J. van Wezel, D. J. Rahn, K. Rossnagel, E. W. Hudson, M. R. Norman, and J. E. Hoffman, Quantum phase transition from triangular to stripe charge order in NbSe2, Proc. Natl. Acad. Sci. USA 110(5), 1623 (2013)

    Article  ADS  Google Scholar 

  19. Y. Umemoto, K. Sugawara, Y. Nakata, T. Takahashi, and T. Sato, Pseudogap, Fermi arc, and Peierls-insulating phase induced by 3D-2D crossover in monolayer VSe2, Nano Res. 12(1), 165 (2019)

    Article  Google Scholar 

  20. Z. J. Li, Y. C. Zhao, K. J. Mu, H. Shan, Y. Q. Guo, J. J. Wu, Y. Q. Su, Q. R. Wu, Z. Sun, A. D. Zhao, X. F. Cui, C. Z. Wu, and Y. Xie, Molecule-confined engineering toward superconductivity and ferromagnetism in two-dimensional superlattice, J. Am. Chem. Soc. 139(45), 16398 (2017)

    Article  Google Scholar 

  21. Y. H. Zhou, B. W. Zhang, X. L. Chen, C. C. Gu, C. An, Y. Zhou, K. M. Cai, Y. F. Yuan, C. H. Chen, H. Wu, R. R. Zhang, C. Y. Park, Y. M. Xiong, X. W. Zhang, K. Y. Wang, and Z. R. Yang, Pressure-induced metallization and robust superconductivity in pristine 1T-SnSe2, Adv. Electron. Mater. 4(8), 1800155 (2018)

    Article  Google Scholar 

  22. J. W. Zeng, E. Liu, Y. J. Fu, Z. Y. Chen, C. Pan, C. Y. Wang, M. Wang, Y. J. Wang, K. Xu, S. H. Cai, X. X. Yan, Y. Wang, X. W. Liu, P. Wang, S. J. Liang, Y. Cui, H. Y. Hwang, H. T. Yuan, and F. Miao, Gate-induced interfacial superconductivity in 1T-SnSe2, Nano Lett. 18(2), 1410 (2018)

    Article  ADS  Google Scholar 

  23. Y. M. Zhang, J. Q. Fan, W. L. Wang, D. Zhang, L. L. Wang, W. Li, K. He, C. L. Song, X. C. Ma, and Q. K. Xue, Observation of interface superconductivity in a SnSe2/epitaxial graphene van der Waals heterostructure, Phys. Rev. B 98(22), 220508 (2018)

    Article  ADS  Google Scholar 

  24. Z. B. Shao, Z. G. Fu, S. J. Li, Y. Cao, Q. Bian, H. G. Sun, Z. Y. Zhang, H. Gedeon, X. Zhang, L. J. Liu, Z. W. Cheng, F. W. Zheng, P. Zhang, and M. H. Pan, Strongly compressed few-layered SnSe2 films grown on a SrTiO3 substrate: The coexistence of charge ordering and enhanced interfacial superconductivity, Nano Lett. 19(8), 5304 (2019)

    Article  ADS  Google Scholar 

  25. P. Yu, X. C. Yu, W. L. Lu, H. Lin, L. F. Sun, K. Z. Du, F. C. Liu, W. Fu, Q. S. Zeng, Z. X. Shen, C. H. Jin, Q. J. Wang, and Z. Liu, Fast photoresponse from 1T tin diselenide atomic layers, Adv. Funct. Mater. 26(1), 137 (2016)

    Article  Google Scholar 

  26. Y. B. Zhang, V. W. Brar, F. Wang, C. Girit, Y. Yayon, M. Panlasigui, A. Zettl, and M. F. Crommie, Giant phonon-induced conductance in scanning tunnelling spectroscopy of gate-tunable graphene, Nat. Phys. 4(8), 627 (2008)

    Article  Google Scholar 

  27. D. W. Shen, Y. Zhang, L. X. Yang, J. Wei, H. W. Ou, J. K. Dong, B. P. Xie, C. He, J. F. Zhao, B. Zhou, M. Arita, K. Shimada, H. Namatame, M. Taniguchi, J. Shi, and D. L. Feng, Primary role of the barely occupied states in the charge density wave formation of NbSe2, Phys. Rev. Lett. 101(22), 226406 (2008)

    Article  ADS  Google Scholar 

  28. K. C. Rahnejat, C. A. Howard, N. E. Shuttleworth, S. R. Schofield, K. Iwaya, C. F. Hirjibehedin, C. Renner, G. Aeppli, and M. Ellerby, Charge density waves in the graphene sheets of the superconductor CaC6, Nat. Commun. 2(1), 1 (2011)

    Article  Google Scholar 

  29. Ø. Fischer, M. Kugler, I. Maggio-Aprile, C. Berthod, and C. Renner, Scanning tunneling spectroscopy of high-temperature superconductors, Rev. Mod. Phys. 79(1), 353 (2007)

    Article  ADS  Google Scholar 

  30. T. Kondo, R. Khasanov, T. Takeuchi, J. Schmalian, and A. Kaminski, Competition between the pseudogap and superconductivity in the high-Tc copper oxides, Nature 457(7227), 296 (2009)

    Article  ADS  Google Scholar 

  31. M. J. Lawler, K. Fujita, J. Lee, A. R. Schmidt, Y. Kohsaka, C. K. Kim, H. Eisaki, S. Uchida, J. C. Davis, J. P. Sethna, and E. A. Kim, Intra-unit-cell electronic nematicity of the high-Tc copper-oxide pseudogap states, Nature 466(7304), 347 (2010)

    Article  ADS  Google Scholar 

  32. K. W. Zhang, C. L. Yang, B. Lei, P. C. Lu, X. B. Li, Z. Y. Jia, Y. H. Song, J. Sun, X. H. Chen, J. X. Li, and S. C. Li, Unveiling the charge density wave inhomogeneity and pseudogap state in 1T-TiSe2, Sci. Bull. 63(7), 426 (2018)

    Article  Google Scholar 

  33. A. Damascelli, Z. Hussain, and Z. X. Shen, Angle-resolved photoemission studies of the cuprate superconductors, Rev. Mod. Phys. 75(2), 473 (2003)

    Article  ADS  Google Scholar 

  34. M. Hashimoto, I. M. Vishik, R. H. He, T. P. Devereaux, and Z. X. Shen, Energy gaps in high-transition-temperature cuprate superconductors, Nat. Phys. 10(7), 483 (2014)

    Article  Google Scholar 

  35. X. Montiel, T. Kloss, C. Pépin, S. Benhabib, Y. Gallais, and A. Sacuto, η collective mode as A1g Raman resonance in cuprate superconductors, Phys. Rev. B 93(2), 024515 (2016)

    Article  ADS  Google Scholar 

  36. T. Shimada, F. S. Ohuchi, and B. A. Parkinson, Work function and photothreshold of layered metal dichalcogenides, Jpn. J. Appl. Phys. 1(33), 2696 (1994)

    Article  ADS  Google Scholar 

  37. H. Ago, T. Kugler, F. Cacialli, K. Petritsch, R. H. Friend, W. R. Salaneck, Y. Ono, T. Yamabe, and K. Tanaka, Work function of purified and oxidised carbon nanotubes, Synth. Met. 103(1–3), 2494 (1999)

    Article  Google Scholar 

  38. Y. Saito, T. Nojima, and Y. Iwasa, Highly crystalline 2D superconductors, Nat. Rev. Mater. 2(1), 1 (2017)

    Article  Google Scholar 

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  1. These authors contributed equally to this work.

Authors and Affiliations

  1. Hefei National Laboratory for Physical Sciences at the Microscale and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, 230026, China

    Ya-Hui Mao, Huan Shan, Jin-Rong Wu, Ze-Jun Li, Chang-Zheng Wu, Xiao-Fang Zhai, Ai-Di Zhao & Bing Wang

  2. School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, China

    Xiao-Fang Zhai & Ai-Di Zhao

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  1. Ya-Hui Mao
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Correspondence to Ai-Di Zhao.

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Mao, YH., Shan, H., Wu, JR. et al. Observation of pseudogap in SnSe2 atomic layers grown on graphite. Front. Phys. 15, 43501 (2020). https://doi.org/10.1007/s11467-020-0977-1

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