Abstract
Intercalation is an effective method to modify physical properties and induce novel electronic states of transition metal dichalcogenide (TMD) materials. However, it is difficult to reveal the microscopic electronic state evolution in the intercalated TMDs. Here we successfully synthesize the copper-intercalated 1T-TaS2 and characterize the structural and electronic modification combining resistivity measurements, atomic-resolution scanning transmission electron microscopy (ADF-STEM), and scanning tunneling microscopy (STM). The intercalated Cu atom is determined to be directly below the Ta atom and suppresses the commensurate charge density wave (CCDW) phase. Two specific electronic modulations are discovered in the near-commensurate (NC) CDW phase: the electron doping state near the defective star of Davids (SDs) in metallic domains and the spatial evolution of the Mott gap in insulating domains. Both modulations reveal that intercalated Cu atoms act as a medium to enhance the interaction between intralayer SDs, in addition to the general charge transfer effect. It also solidifies the Mott foundation of the insulating gap in pristine samples. The intriguing electronic evolution in Cu-intercalated 1T-TaS2 will motivate further exploration of novel electronic states in the intercalated TMD materials.
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Wilson, J. A.; Di Salvo, F. J.; Mahajan, S. Charge-density waves and superlattices in the metallic layered transition metal dichalcogenides. Adv. Phys. 1975, 24, 117–201.
Fazekas, P.; Tosatti, E. Electrical, structural and magnetic properties of pure and doped 1T-TaS2. Philos. Mag. B 1979, 39, 229–244.
Kim, J. J.; Yamaguchi, W.; Hasegawa, T.; Kitazawa, K. Observation of Mott localization gap using low temperature scanning tunneling spectroscopy in commensurate 1T-TaS2. Phys. Rev. Lett. 1994, 73, 2103–2106.
Law, K. T.; Lee, P. A. 1T-TaS2 as a quantum spin liquid. Proc. Natl. Acad. Sci. USA. 2017, 114, 6996–7000.
Sipos, B.; Kusmartseva, A. F.; Akrap, A.; Berger, H.; Forró, L.; Tutiš, E. From Mott state to superconductivity in 1T-TaS2. Nat. Mater. 2008, 7, 960–965.
Ang, R.; Tanaka, Y.; Ieki, E.; Nakayama, K.; Sato, T.; Li, L. J.; Lu, W. J.; Sun, Y. P.; Takahashi, T. Real-space coexistence of the melted Mott state and superconductivity in Fe-substituted 1T-TaS2. Phys. Rev. Lett. 2012, 109, 176403.
Liu, Y.; Ang, R.; Lu, W. J.; Song, W. H.; Li, L. J.; Sun, Y. P. Superconductivity induced by Se-doping in layered charge-density-wave system 1T-TaS2−xSex. Appl. Phys. Lett. 2013, 102, 192602.
Qiao, S.; Li, X. T.; Wang, N. Z.; Ruan, W.; Ye, C.; Cai, P.; Hao, Z. Q.; Yao, H.; Chen, X. H.; Wu, J. et al. Mottness collapse in 1T-TaS2−xSex transition-metal dichalcogenide: An interplay between localized and itinerant orbitals. Phys. Rev. X 2017, 7, 041054.
Yu, Y. J.; Yang, F. Y.; Lu, X. F.; Yan, Y. J.; Cho, Y. H.; Ma, L. G.; Niu, X. H.; Kim, S.; Son, Y. W.; Feng, D. L. et al. Gate-tunable phase transitions in thin flakes of 1T-TaS2. Nat. Nanotechnol. 2015, 10, 270–276.
Ritschel, T.; Trinckauf, J.; Koepernik, K.; Büchner, B.; Zimmermann, M. V.; Berger, H.; Joe, Y. I.; Abbamonte, P.; Geck, J. Orbital textures and charge density waves in transition metal dichalcogenides. Nat. Phys. 2015, 11, 328–331.
Lee, S. H.; Goh, J. S.; Cho, D. Origin of the insulating phase and first-order metal-insulator transition in 1T-TaS2. Phys. Rev. Lett. 2019, 122, 106404.
Shin, D.; Tancogne-Dejean, N.; Zhang, J.; Okyay, M. S.; Rubio, A.; Park, N. Identification of the Mott insulating charge density wave state in 1T-TaS2. Phys. Rev. Lett. 2021, 126, 196406.
Butler, C. J.; Yoshida, M.; Hanaguri, T.; Iwasa, Y. Mottness versus unit-cell doubling as the driver of the insulating state in 1T-TaS2. Nat. Commun. 2020, 11, 2477.
Wang, Y. D.; Yao, W. L.; Xin, Z. M.; Han, T. T.; Wang, Z. G.; Chen, L.; Cai, C.; Li, Y.; Zhang, Y. Band insulator to Mott insulator transition in 1T-TaS2. Nat. Commun. 2020, 11, 4215.
Stahl, Q.; Kusch, M.; Heinsch, F.; Garbarino, G.; Kretzschmar, N.; Hanff, K.; Rossnagel, K.; Geck, J.; Ritschel, T. Collapse of layer dimerization in the photo-induced hidden state of 1T-TaS2. Nat. Commun. 2020, 11, 1247.
Wan, J. Y.; Lacey, S. D.; Dai, J. Q.; Bao, W. Z.; Fuhrer, M. S.; Hu, L. B. Tuning two-dimensional nanomaterials by intercalation: Materials, properties, and applications. Chem. Soc. Rev. 2016, 45, 6742–6765.
Wang, Z. Y.; Li, R. L.; Su, C. L.; Loh, K. P. Intercalated phases of transition metal dichalcogenides. SmartMat 2020, 1, e1013.
Liu, X. C.; Zhao, S. Y.; Sun, X. P.; Deng, L. Z.; Zou, X. L.; Hu, Y. C.; Wang, Y. X.; Chu, C. W.; Li, J.; Wu, J. J. et al. Spontaneous self-intercalation of copper atoms into transition metal dichalcogenides. Sci. Adv. 2020, 6, eaay4092.
Zhang, J. S.; Sun, J.; Li, Y. B.; Shi, F. F.; Cui, Y. Electrochemical control of copper intercalation into nanoscale Bi2Se3. Nano Lett. 2017, 17, 1741–1747.
Wang, P. D.; Khan, R.; Liu, Z. F.; Zhang, B.; Li, Y. L.; Wang, S.; Wu, Y. B.; Zhu, H. E.; Liu, Y.; Zhang, G. B. et al. A Non-rigid shift of band dispersions induced by Cu intercalation in 2H-TaSe2. Nano Res. 2020, 13, 353–357.
Novello, A. M.; Spera, M.; Scarfato, A.; Ubaldini, A.; Giannini, E.; Bowler, D. R.; Renner, C. Stripe and short range order in the charge density wave of 1T-CuxTaSe2. Phys. Rev. Lett. 2017, 118, 017002.
Yan, S. C.; Iaia, D.; Morosan, E.; Fradkin, E.; Abbamonte, P.; Madhavan, V. Influence of domain walls in the incommensurate charge density wave state of Cu intercalated 1T-TaSe2. Phys. Rev. Lett. 2017, 118, 106405.
Qian, D.; Hsieh, D.; Wray, L.; Morosan, E.; Wang, N. L.; Xia, Y.; Cava, R. J.; Hasan, M. Z. Emergence of Fermi pockets in a new excitonic charge-density-wave melted superconductor. Phys. Rev. Lett. 2007, 98, 117007.
Zhang, K. W.; Yang, C. L.; Lei, B.; Lu, P. C.; Li, X. B.; Jia, Z. Y.; Song, Y. H.; Sun, J.; Chen, X. H.; Li, J. X. et al. Unveiling the charge density wave inhomogeneity and pseudogap state in 1T-TaSe2. Sci. Bull. 2018, 63, 426–432.
Wu, Z. X.; Bu, K. L.; Zhang, W. H.; Fei, Y.; Zheng, Y.; Gao, J. J.; Luo, X.; Liu, Z.; Sun, Y. P.; Yin, Y. Effect of stacking order on the electronic state of 1T-TaS2. Phys. Rev. B. 2022, 105, 035109.
Bu, K. L.; Zhang, W. H.; Fei, Y.; Wu, Z. X.; Zheng, Y.; Gao, J. J.; Luo, X.; Sun, Y. P.; Yin, Y. Possible strain induced Mott gap collapse in 1T-TaS2. Commun. Phys. 2019, 2, 146.
Lahoud, E.; Meetei, O. N.; Chaska, K. B.; Kanigel, A.; Trivedi, N. Emergence of a novel pseudogap metallic state in a disordered 2D Mott insulator. Phys. Rev. Lett. 2014, 112, 206402.
Lee, P. A.; Ramakrishnan, T. V. Disordered electronic systems. Rev. Mod. Phys. 1985, 57, 287–337.
Szabo, J. C.; Lee, K.; Madhavan, V.; Trivedi, N. Local spectroscopies reveal percolative metal in disordered Mott insulators. Phys. Rev. Lett. 2020, 124, 137402.
Regan, E. C.; Wang, D. Q.; Jin, C. H.; Utama, M. I. B.; Gao, B. N.; Wei, X.; Zhao, S. H.; Zhao, W. Y.; Zhang, Z. C.; Yumigeta, K. et al. Mott and generalized Wigner crystal states in WSe2/WS2 Moiré superlattices. Nature 2020, 579, 359–363.
Zhang, Y.; Gao, F.; Gao, S. W.; He, L. Tunable magnetism of a single-carbon vacancy in graphene. Sci. Bull. 2020, 65, 194–200.
Cho, D.; Gye, G.; Lee, J.; Lee, S. H.; Wang, L. H.; Cheong, S. W.; Yeom, H. W. Correlated electronic states at domain walls of a Mottcharge-density-wave insulator 1T-TaS2. Nat. Commun. 2017, 8, 392.
Skolimowski, J.; Gerasimenko, Y.; Žitko, R. Mottness collapse without metallization in the domain wall of the triangular-lattice Mott insulator 1T-TaS2. Phys. Rev. Lett. 2019, 122, 036802.
Park, J. W.; Lee, J.; Yeom, H. W. Zoology of domain walls in quasi-2D correlated charge density wave of 1T-TaS2. npj Quantum Mater. 2021, 6, 32.
Ye, C.; Cai, P.; Yu, R. Z.; Zhou, X. D.; Ruan, W.; Liu, Q. Q.; Jin, C. Q.; Wang, Y. Y. Visualizing the atomic-scale electronic structure of the Ca2CuO2Cl2 Mott insulator. Nat. Commun. 2013, 4, 1365.
Eskes, H.; Meinders, M. B. J.; Sawatzky, G. A. Anomalous transfer of spectral weight in doped strongly correlated systems. Phys. Rev. Lett. 1991, 67, 1035–1038.
Klanjšek, M.; Zorko, A.; Žitko, R.; Mravlje, J.; Jagličić, Z.; Biswas, P. K.; Prelovšek, P.; Mihailovic, D.; Arčon, D. A high-temperature quantum spin liquid with polaron spins. Nat. Phys. 2017, 13, 1130–1134.
Acknowledgements
Dr. Yonghui Zheng and Prof. Yan Cheng at East China Normal University were acknowledged for their kind assistance on the access to FIB and ADF-STEM used in this study. This work was supported by the National Key Research and Development Program (No. 2019YFA0308602), the Key Research and Development Program of Zhejiang Province, China (No. 2021C01002), Vacuum Interconnected Nanotech Workstation (Nano-X) (B2004) and the Fundamental Research Funds for the Central Universities in China. D. D. and C. J. thank the National Natural Science Foundation of China (Nos. NSFC-51772265 and NSFC-61721005), J. G., W. W., X. L., W. L., and Y. S. thank the support of the National Key Research and Development Program (No. 2016YFA0300404), the National Natural Science Foundation of China (Nos. NSFC-11674326 and NSFC-11874357), the Joint Funds of the National Natural Science Foundation of China, and the Chinese Academy of Sciences’ Large-scale Scientific Facility (Nos. U1832141, U1932217, and U2032215).
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Zhang, W., Ding, D., Gao, J. et al. Modulation of electronic state in copper-intercalated 1T-TaS2. Nano Res. 15, 4327–4333 (2022). https://doi.org/10.1007/s12274-021-4034-3
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DOI: https://doi.org/10.1007/s12274-021-4034-3