Details

Autor(en) / Beteiligte

• Lou, Rui
• Guo, Pengjie
• Li, Man
• Wang, Qi
• Liu, Zhonghao
• Sun, Shanshan
• Li, Chenghe
• Wu, Xuchuan
• Wang, Zilu
• Sun, Zhe
• Shen, Dawei
• Huang, Yaobo
• Liu, Kai
• Lu, Zhong-Yi
• Lei, Hechang
• Ding, Hong
• Wang, Shancai

Titel

Experimental observation of bulk nodal lines and electronic surface states in ZrB2

Ist Teil von

• npj quantum materials, 2018-09, Vol.3 (1), Article 43

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2018

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Topological nodal-line semimetals are characterized by line-contact bulk band crossings and topological surface states. Breaking certain protecting symmetry turns this system into a Dirac semimetal or Weyl semimetal that hosts zero-dimensional isolated nodal points. Recent advances in band theory predicted a topological nodal-line semimetal state possessing a new type of nodal line in AlB 2 -type diborides. Here, we report an experimental realization of nodal-line fermions and associated surface states near the Fermi energy in ZrB 2 by angle-resolved photoemission spectroscopy combined with first-principles calculations. The Dirac nodal lines in ZrB 2 wind into two groups of nodal rings, which are linked together along the Γ- K direction. We further observe a distinct surface state connecting to each nodal line, indicative of the nontrivial topological nature of the bulk nodal lines. Therefore, our results provide convincing experimental evidence of nodal-line semimetal states in ZrB 2 both in the bulk and on the surface, suggesting ZrB 2 as a remarkable platform for discovering unique phenomena induced by nodal-line fermions. Topological materials: Drumhead surface states observed at last A new type of quantum state located at the surface of a topological material has been observed. A collaboration of researchers led by Shancai Wang from Renmin University of China used photoemission spectroscopy to visualise the band structure of ZrB 2 to confirm its topological properties predicted by density functional theory calculations. They found strong evidence for two groups of nodal rings—topologically-protected crossings between two bands that are extended in a loop through momentum space—and the previously-unobserved “drumhead” surface states that fill out the loops. The surface states in ZrB 2 lie close to the Fermi energy and are sharply distinct from the bulk bands, so this material is an excellent candidate for further investigations of the unique properties of nodal line semimetals. If you feel that the title is too narrow, it could be replaced with Topological materials: New type of surface state observed in ZrB 2 .