Ebad-Allah, J., Afonso, J. F., Krottenmüller, M., Hu, J., Zhu, Y. L., Mao, Z. Q., Kuneš, J., & Kuntscher, C. A. (2019). Chemical pressure effect on the optical conductivity of the nodal-line semimetals ZrSiY (Y= S,Se,Te) and ZrGeY (Y= S,Te). Physical Review B, 99, Article 125154. https://doi.org/10.1103/PhysRevB.99.125154
E138-02 - Forschungsbereich Correlations: Theory and Experiments
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Journal:
Physical Review B
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ISSN:
2469-9950
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Date (published):
29-Mar-2019
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Publisher:
AMER PHYSICAL SOC
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Peer reviewed:
Yes
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Keywords:
Nodal semimetal
en
Abstract:
ZrSiS is a nodal-line semimetal, whose electronic band structure contains a diamond-shaped line of Dirac nodes. We carried out a comparative study on the optical conductivity of ZrSiS and the related compounds ZrSiSe, ZrSiTe, ZrGeS, and ZrGeTe by reflectivity measurements over a broad frequency range combined with density functional theory calculations. The optical conductivity exhibits a distinct U shape, ending at a sharp peak at around 10000cm-1 for all studied compounds except for ZrSiTe. The U shape of the optical conductivity is due to transitions between the linearly dispersing bands crossing each other along the nodal line. The sharp high-energy peak is related to transitions between almost parallel bands, and its energy position depends on the interlayer bonding correlated with the c/a ratio, which can be tuned by either chemical or external pressure. For ZrSiTe, another pair of crossing bands appears in the vicinity of the Fermi level, corrugating the nodal-line electronic structure and leading to the observed difference in optical conductivity. The findings suggest that the Dirac physics in ZrXY compounds with X=Si,Ge and Y=S,Se,Te is closely connected to the interlayer bonding.