中国物理B ›› 2021, Vol. 30 ›› Issue (8): 87306-087306.doi: 10.1088/1674-1056/abff32

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Signatures of strong interlayer coupling in γ-InSe revealed by local differential conductivity

Xiaoshuai Fu(富晓帅), Li Liu(刘丽), Li Zhang(张力), Qilong Wu(吴奇龙), Yu Xia(夏雨), Lijie Zhang(张利杰), Yuan Tian(田园), Long-Jing Yin(殷隆晶), and Zhihui Qin(秦志辉)   

  1. Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
  • 收稿日期:2021-04-21 修回日期:2021-04-28 接受日期:2021-05-08 出版日期:2021-07-16 发布日期:2021-07-23
  • 通讯作者: Li Zhang, Zhihui Qin E-mail:li_zhang@hnu.edu.cn;zhqin@hnu.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51772087, 11804089, 11574350, 11904094, and 51972106), the Natural Science Foundation of Hunan Province, China (Grant Nos. 2018JJ3025, 2019JJ50034, and 2019JJ50073), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB30000000), and the Fundamental Research Funds for the Central Universities of China.

Signatures of strong interlayer coupling in γ-InSe revealed by local differential conductivity

Xiaoshuai Fu(富晓帅), Li Liu(刘丽), Li Zhang(张力), Qilong Wu(吴奇龙), Yu Xia(夏雨), Lijie Zhang(张利杰), Yuan Tian(田园), Long-Jing Yin(殷隆晶), and Zhihui Qin(秦志辉)   

  1. Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education&Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
  • Received:2021-04-21 Revised:2021-04-28 Accepted:2021-05-08 Online:2021-07-16 Published:2021-07-23
  • Contact: Li Zhang, Zhihui Qin E-mail:li_zhang@hnu.edu.cn;zhqin@hnu.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 51772087, 11804089, 11574350, 11904094, and 51972106), the Natural Science Foundation of Hunan Province, China (Grant Nos. 2018JJ3025, 2019JJ50034, and 2019JJ50073), the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB30000000), and the Fundamental Research Funds for the Central Universities of China.

摘要: Interlayer coupling in layered semiconductors can significantly affect their optoelectronic properties. However, understanding the mechanisms behind the interlayer coupling at the atomic level is not straightforward. Here, we study modulations of the electronic structure induced by the interlayer coupling in the γ-phase of indium selenide (γ-InSe) using scanning probe techniques. We observe a strong dependence of the energy gap on the sample thickness and a small effective mass along the stacking direction, which are attributed to strong interlayer coupling. In addition, the moiré patterns observed in γ-InSe display a small band-gap variation and nearly constant local differential conductivity along the patterns. This suggests that modulation of the electronic structure induced by the moiré potential is smeared out, indicating the presence of a significant interlayer coupling. Our theoretical calculations confirm that the interlayer coupling in γ-InSe is not only of the van der Waals origin, but also exhibits some degree of hybridization between the layers. Strong interlayer coupling might play an important role in the performance of γ-InSe-based devices.

关键词: indium selenide (InSe), interlayer coupling, scanning tunneling microscopy/spectroscopy (STM/STS), density functional theory

Abstract: Interlayer coupling in layered semiconductors can significantly affect their optoelectronic properties. However, understanding the mechanisms behind the interlayer coupling at the atomic level is not straightforward. Here, we study modulations of the electronic structure induced by the interlayer coupling in the γ-phase of indium selenide (γ-InSe) using scanning probe techniques. We observe a strong dependence of the energy gap on the sample thickness and a small effective mass along the stacking direction, which are attributed to strong interlayer coupling. In addition, the moiré patterns observed in γ-InSe display a small band-gap variation and nearly constant local differential conductivity along the patterns. This suggests that modulation of the electronic structure induced by the moiré potential is smeared out, indicating the presence of a significant interlayer coupling. Our theoretical calculations confirm that the interlayer coupling in γ-InSe is not only of the van der Waals origin, but also exhibits some degree of hybridization between the layers. Strong interlayer coupling might play an important role in the performance of γ-InSe-based devices.

Key words: indium selenide (InSe), interlayer coupling, scanning tunneling microscopy/spectroscopy (STM/STS), density functional theory

中图分类号:  (Surface states, band structure, electron density of states)

  • 73.20.At
68.37.Ef (Scanning tunneling microscopy (including chemistry induced with STM)) 71.15.Mb (Density functional theory, local density approximation, gradient and other corrections)