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hourglass fermion, Dirac nodal line, ARPES, angle-resolved photoemission spectroscopy
The Collaborative Research of NSRRC Scientist Ro-Ya Liu and NSRRC User Tai-Chang Chiang Featured on a Cover of Nano Letters
Dr. Ro-Ya Liu of the NSRRC, Academician Tai-Chang Chiang and their collaborators presented spectroscopic signatures of a topological hourglass semimetal phase from ARPES, and the research findings were featured on a cover of Nano Letters.
NSRRC scientist Dr. Ro-Ya Liu and NSRRC user Academician Tai-Chang Chiang (University of Illinois at Urbana−Champaign, USA), who also serves in the NSRRC Science Advisory Committee, assembled an international research team for studying the phenomena of hourglass fermion in condensed-matter physics by using TLS 21B1 at the NSRRC and other facilities. Their research findings were released in Nano Letters and were featured on a cover of the January 11 issue.

Based on the literature reviews on topological research, it was predicted in 2016 and 2018 that two different kinds of materials would contain the hourglass fermion, a new kind of electronic state, exhibiting the three-dimensional quantum spin Hall effect as well as unique hourglass-shaped dispersion relation. The team examined the electronic structure of layered semi-metallic material Nb3SiTe6 using angle-resolved photoemission spectroscopy (ARPES), scanning tunneling microscopy, X-ray diffraction, and other technologies. They found the electronic spin flow in this system in addition to the intriguing hourglass fermion's Dirac nodal lines. Simple proofs were offered in this research to help readers comprehend the hourglass fermion better.