| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Observation of Tunneling Gap in Epitaxial Ultrathin Films of Pyrite-Type Copper Disulfide |
| Chong Liu1, Haohao Yang1, Can-Li Song1,2, Wei Li1,2, Ke He1,2, Xu-Cun Ma1,2, Lili Wang1,2**, Qi-Kun Xue1,2** |
1State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084
2Collaborative Innovation Center of Quantum Matter, Beijing 100084 |
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| Cite this article: |
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Chong Liu, Haohao Yang, Can-Li Song et al 2018 Chin. Phys. Lett. 35 027303 |
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Abstract We report scanning tunneling microscopy investigation on epitaxial ultrathin films of pyrite-type copper disulfide. Layer-by-layer growth of CuS$_{2}$ films with a preferential orientation of (111) on SrTiO$_{3}$(001) and Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+\delta}$ substrates is achieved by molecular beam epitaxy growth. For ultrathin films on both kinds of substrates, we observe symmetric tunneling gap around the Fermi level that persists up to $\sim$15 K. The tunneling gap degrades with either increasing temperature or increasing thickness, suggesting new matter states at the extreme two-dimensional limit.
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Received: 15 January 2018
Published: 23 January 2018
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| PACS: |
73.20.At
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(Surface states, band structure, electron density of states)
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81.15.Hi
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(Molecular, atomic, ion, and chemical beam epitaxy)
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68.37.Ef
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(Scanning tunneling microscopy (including chemistry induced with STM))
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| Fund: Supported by the National Natural Science Foundation of China under Grant Nos 11574174, 11774193 and 11790311, and the National Basic Research Program of China under Grant No 2015CB921000. |
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