1. Revealing the EuCd_{2}As_{2} Semiconducting Band Gap via n-type La-Doping
- Author
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Nelson, Ryan A., King, Jesaiah, Cheng, Shuyu, Williams, Archibald J., Jozwiak, Christopher, Bostwick, Aaron, Rotenberg, Eli, Sasmal, Souvik, Kao, I-Hsuan, Tiwari, Aalok, Jones, Natalie R., Cai, Chuting, Martin, Emma, Dolocan, Andrei, Shi, Li, Kawakami, Roland, Heremans, Joseph P., Katoch, Jyoti, and Goldberger, Joshua E.
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Condensed Matter - Materials Science - Abstract
EuCd_{2}As_{2} has attracted considerable interest as one of the few magnetic Weyl semimetal candidate materials, although recently there have been emerging reports that claim it to have a semiconducting electronic structure. To resolve this debate, we established the growth of n-type EuCd_{2}As_{2} crystals, to directly visualize the nature of the conduction band using angle resolve photoemission spectroscopy (ARPES). We show that La-doping leads to n-type transport signatures in both the thermopower and Hall effect measurements, in crystals with doping levels at 2 - 6 x 10^{17} e^{-} cm^{-3}. Both p-type and n-type doped samples exhibit antiferromagnetic ordering at 9 K. ARPES experiments at 6 K clearly show the presence of the conduction band minimum at 0.8 eV above the valence band maximum, which is further corroborated by the observation of a 0.71 - 0.72 eV band gap in room temperature diffuse reflectance absorbance measurements. Together these findings unambiguously show that EuCd_{2}As_{2} is indeed a semiconductor with a substantial band gap and not a topological semimetal.
- Published
- 2024
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