首页|Manipulation of band gap in 1T-TiSe2 via rubidium deposition

Manipulation of band gap in 1T-TiSe2 via rubidium deposition

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The 1T-TiSe2 is a two-dimensional charge-density-wave(CDW)material that attracts great interest.A small band gap locates at the Fermi level separating the Ti d-bands and Se p-bands,which makes 1T-TiSe2 a promising candidate for realizing excitonic condensation.Here,we studied the band gap in lT-TiSe2 using angle-resolved photoemission spectroscopy(ARPES).Instead of only focusing on the in-plane band dispersions,we obtained the detailed band dispersions of both conduction and valance bands along the out-of-plane direction.We found that the conduction and valance bands split into multiple sub-bands in the CDW state due to band folding.As a result,the band gap between the Ti d-bands and Se p-bands reduces to～25 meV and becomes a direct gap in the CDW state.More intriguingly,such band gap can be further reduced by the rubidium deposition.The band structure becomes semimetallic in the rubidium-doped sample.Meanwhile,exotic gapless behaviors were observed at the p-d band crossing.Our result characterized the band gap of lT-TiSe2 in three-dimensional Brillouin zone with unpreceded precision.It also suggests a closing of band gap or a potential band inversion in 1T-TiSe2 driven by rubidium deposition.

angle-resolved photoemission spectroscopymetal-insulator transitiontransition metal dichalco-genides

欧仪、陈磊、信子鸣、任宇靖、袁鹏浩、王政国、朱玉、陈景芝、张焱

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International Center for Quantum Materials,School of Physics,Peking University,Beijing 100871,China

National Key Research and Development Program of ChinaNational Key Research and Development Program of ChinaNational Natural Science Foundation of ChinaME2 project from the National Natural Science Foundation of China

2022YFA14035022018YFA03056021188810111227901

2024

10.1088/1674-1056/ad48f9

中国物理B(英文版)
中国物理学会和中国科学院物理研究所

中国物理B(英文版)

CSTPCDEI
影响因子：0.995
ISSN：1674-1056
年,卷(期)：2024.33(8)