中国物理B ›› 2022, Vol. 31 ›› Issue (6): 67401-067401.doi: 10.1088/1674-1056/ac65f2

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Experimental observation of pseudogap in a modulation-doped Mott insulator: Sn/Si(111)-(√30×√30)R30°

Yan-Ling Xiong(熊艳翎)1, Jia-Qi Guan(关佳其)1, Rui-Feng Wang(汪瑞峰)1, Can-Li Song(宋灿立)1,2,†, Xu-Cun Ma(马旭村)1,2,‡, and Qi-Kun Xue(薛其坤)1,2,3,4   

  1. 1 State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China;
    2 Frontier Science Center for Quantum Information, Beijing 100084, China;
    3 Beijing Academy of Quantum Information Sciences, Beijing 100193, China;
    4 Southern University of Science and Technology, Shenzhen 518055, China
  • 收稿日期:2022-03-01 修回日期:2022-03-28 接受日期:2022-04-11 出版日期:2022-05-17 发布日期:2022-05-31
  • 通讯作者: Can-Li Song, Xu-Cun Ma E-mail:clsong07@mail.tsinghua.edu.cn;xucunma@mail.tsinghua.edu.cn
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 62074092 and 11604366) and the National Key R&D Program of China (Grant No. 2018YFA0305603).

Experimental observation of pseudogap in a modulation-doped Mott insulator: Sn/Si(111)-(√30×√30)R30°

Yan-Ling Xiong(熊艳翎)1, Jia-Qi Guan(关佳其)1, Rui-Feng Wang(汪瑞峰)1, Can-Li Song(宋灿立)1,2,†, Xu-Cun Ma(马旭村)1,2,‡, and Qi-Kun Xue(薛其坤)1,2,3,4   

  1. 1 State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China;
    2 Frontier Science Center for Quantum Information, Beijing 100084, China;
    3 Beijing Academy of Quantum Information Sciences, Beijing 100193, China;
    4 Southern University of Science and Technology, Shenzhen 518055, China
  • Received:2022-03-01 Revised:2022-03-28 Accepted:2022-04-11 Online:2022-05-17 Published:2022-05-31
  • Contact: Can-Li Song, Xu-Cun Ma E-mail:clsong07@mail.tsinghua.edu.cn;xucunma@mail.tsinghua.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 62074092 and 11604366) and the National Key R&D Program of China (Grant No. 2018YFA0305603).

摘要: Unusual quantum phenomena usually emerge upon doping Mott insulators. Using a molecular beam epitaxy system integrated with cryogenic scanning tunneling microscope, we investigate the electronic structure of a modulation-doped Mott insulator Sn/Si(111)-($\sqrt{3}\times \sqrt{3})R$30$^\circ$. In underdoped regions, we observe a universal pseudogap opening around the Fermi level, which changes little with the applied magnetic field and the occurrence of Sn vacancies. The pseudogap gets smeared out at elevated temperatures and alters in size with the spatial confinement of the Mott insulating phase. Our findings, along with the previously observed superconductivity at a higher doping level, are highly reminiscent of the electronic phase diagram in the doped copper oxide compounds.

关键词: pseudogap (PG), modulation doping, Mott insulator, scanning tunneling microscope (STM)

Abstract: Unusual quantum phenomena usually emerge upon doping Mott insulators. Using a molecular beam epitaxy system integrated with cryogenic scanning tunneling microscope, we investigate the electronic structure of a modulation-doped Mott insulator Sn/Si(111)-($\sqrt{3}\times \sqrt{3})R$30$^\circ$. In underdoped regions, we observe a universal pseudogap opening around the Fermi level, which changes little with the applied magnetic field and the occurrence of Sn vacancies. The pseudogap gets smeared out at elevated temperatures and alters in size with the spatial confinement of the Mott insulating phase. Our findings, along with the previously observed superconductivity at a higher doping level, are highly reminiscent of the electronic phase diagram in the doped copper oxide compounds.

Key words: pseudogap (PG), modulation doping, Mott insulator, scanning tunneling microscope (STM)

中图分类号:  (Pseudogap regime)

  • 74.72.Kf
81.15.-z (Methods of deposition of films and coatings; film growth and epitaxy) 68.37.Ef (Scanning tunneling microscopy (including chemistry induced with STM)) 68.37.-d (Microscopy of surfaces, interfaces, and thin films)