摘要
Nodal line semimetal(NLS) is a new quantum state hosting one-dimensional closed loops formed by the crossing of two bands. The so-called type-Ⅱ NLS means that these two crossing bands have the same sign in their slopes along the radial direction of the loop, which requires that the crossing bands are either right-tilted or left-tilted at the same time. According to the theoretical prediction, Mg3Bi2 is an ideal candidate for studying the type-Ⅱ NLS by tuning its spin-orbit coupling(SOC). High-quality Mg3 Bi2 films are grown by molecular beam epitaxy(MBE). By in-situ angle resolved photoemission spectroscopy(ARPES), a pair of surface resonance bands around theГ point are clearly seen. This shows that Mg3Bi2 films grown by MBE are Mg(1)-terminated by comparing the ARPES spectra with the first principles calculations results. Moreover, the temperature dependent weak anti-localization effect in Mg3Bi2 films is observed under magneto-transport measurements, which shows clear two-dimensional(2 D) e-e scattering characteristics by fitting with the Hikami–Larkin–Nagaoka model. Therefore, by combining with ARPES, magneto-transport measurements and the first principles calculations, this work proves that Mg3Bi2 is a semimetal with topological surface states. This paves the way for Mg3Bi2 to be used as an ideal material platform to study the exotic features of type-Ⅱ nodal line semimetals and the topological phase transition by tuning its SOC.
Nodal line semimetal（NLS） is a new quantum state hosting one-dimensional closed loops formed by the crossing of two bands. The so-called type-Ⅱ NLS means that these two crossing bands have the same sign in their slopes along the radial direction of the loop, which requires that the crossing bands are either right-tilted or left-tilted at the same time. According to the theoretical prediction, Mg3Bi2 is an ideal candidate for studying the type-Ⅱ NLS by tuning its spin-orbit coupling（SOC）. High-quality Mg3 Bi2 films are grown by molecular beam epitaxy（MBE）. By in-situ angle resolved photoemission spectroscopy（ARPES）, a pair of surface resonance bands around the■ point are clearly seen. This shows that Mg3Bi2 films grown by MBE are Mg（1）-terminated by comparing the ARPES spectra with the first principles calculations results. Moreover, the temperature dependent weak anti-localization effect in Mg3Bi2 films is observed under magneto-transport measurements, which shows clear two-dimensional（2 D） e-e scattering characteristics by fitting with the Hikami–Larkin–Nagaoka model. Therefore, by combining with ARPES, magneto-transport measurements and the first principles calculations, this work proves that Mg3Bi2 is a semimetal with topological surface states. This paves the way for Mg3Bi2 to be used as an ideal material platform to study the exotic features of type-Ⅱ nodal line semimetals and the topological phase transition by tuning its SOC.
作者
Tong Zhou
Xie-Gang Zhu
Mingyu Tong
Yun Zhang
Xue-Bing Luo
Xiangnan Xie()
Wei Feng
Qiuyun Chen
Shiyong Tan
Zhen-Yu Wang
Tian Jiang
Yuhua Tang
Xin-Chun Lai
Xuejun Yang
周侗;朱燮刚;童明玉;张云;罗学兵;谢向男;冯卫;陈秋云;谭世勇;王振宇;江天;唐玉华;赖新春;杨学军(State Key Laboratory of High Performance Computing,College of Computer,National University of Defense Technology,Changsha 410073;Science and Technology on Surface Physics and Chemistry Laboratory,Jiangyou 621908;National Innovation Institute of Defense Technology,Academy of Military Sciences PLA China,Beijing 100010;Institute of Materials,China Academy of Engineering Physics,Mianyang 621700;College of Advanced Interdisciplinary Studies,National University of Defense Technology,Changsha 410073;Academy of Military Sciences PLA China,Beijing 100010;Beijing Academy of Quantum Information Sciences,Beijing 100084)
基金
Supported by the Science Challenge Project under Grant No TZ2016004
the Opening Foundation of State Key Laboratory of High Performance Computing under Grant No 201601-02
the Foundation of President of CAEP under Grant No 201501040
the Natural Science Foundation of Hunan Province under Grant No 2016JJ1021
the National Basic Research Program of China under Grant Nos 2015CB921303 and 2012YQ13012508
the General Program of Beijing Academy of Quantum Information Sciences under Grant No Y18G17
the Youth Talent Lifting Project under Grant No 17-JCJQ-QT-004
