Unusual electronic structure of Dirac material BaMnSb2 revealed by angle-resolved photoemission spectroscopy* *Project supported by the National Key Research and Development Program of China (Grant Nos. 2016YFA0300600, 2018YFA0305602, 2016YFA0300300, and 2017YFA0302900), the National Natural Science Foundation of China (Grant Nos. 11974404, 11888101, 11922414, and 11404175), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant Nos. XDB33000000 and XDB25000000), the Youth Innovation Promotion Association of CAS (Grant No. 2017013), and the Natural Science Foundation of Henan Province, China (Grant Nos. 182300410274 and 202300410296). The theoretical calculations are supported by the National Natural Science Foundation of China (Grant Nos. 11674369, 11865019, and 11925408), the Beijing Natural Science Foundation, China (Grant No. Z180008), Beijing Municipal Science and Technology Commission, China (Grant No. Z191100007219013), the National Key Research and Development Program of China (Grant Nos. 2016YFA0300600 and 2018YFA0305700), the K. C.Wong Education Foundation (Grant No. GJTD- 2018-01), and the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No. XDB33000000).

Abstract

High resolution angle resolved photoemission measurements and band structure calculations are carried out to study the electronic structure of BaMnSb2. All the observed bands are nearly linear that extend to a wide energy range. The measured Fermi surface mainly consists of one hole pocket around Γ and a strong spot at Y which are formed from the crossing points of the linear bands. The measured electronic structure of BaMnSb2 is unusual and deviates strongly from the band structure calculations. These results will stimulate further efforts to theoretically understand the electronic structure of BaMnSb2 and search for novel properties in this Dirac material.