Spectroscopic signatures of magnetization-induced band renormalization and strong spin charge lattice coupling in EuZn2As2
DOKPE
- liao, Zhiyou ORCID Chinese Academy of Sciences, Beijing
- Li, Boxuan ORCID University of Chinese Academy of Sciences, Beijing
- Marsik, Premysl ORCID University of Fribourg
- Bernhard, Christian ORCID University of Fribourg
- 2025
Published in:
- Physical Review B. - American Physical Society (APS). - 2025, vol. 111, no. 15
English
We report an infrared spectroscopy study of the antiferromagnetic (AFM) insulator EuZn2As2 over a broad
frequency range, spanning temperatures both above and below the AFM transition TN 20 K. The optical
response reveals an insulating behavior, featuring two prominent infrared-active phonon modes at around 95
and 190 cm−1, and two subtle absorption peaks at around 130 (α peak) and 2 700 cm−1 (β peak), along with
a strong absorption edge rising around 9000 cm−1 (γ peak). Significantly, the temperature-dependent changes
in these peaks show noticeable anomalies across the AFM transition, particularly the emergence of the α peak
and an unusual redshift of the γ peak, suggesting a strong interaction between the charge excitations and the
AFM order. Band-structure calculations reveal that these anomalies arise from magnetization-induced band
renormalizations, including shifts and foldings. Additionally, both phonon modes feature asymmetric Fano line
shapes at low temperatures, with the 95 cm−1 phonon mode exhibiting strong coupling to the fluctuations of Eu
spins. These findings highlight a complex interplay of spin, charge, and lattice degrees of freedom in EuZn2As2.
frequency range, spanning temperatures both above and below the AFM transition TN 20 K. The optical
response reveals an insulating behavior, featuring two prominent infrared-active phonon modes at around 95
and 190 cm−1, and two subtle absorption peaks at around 130 (α peak) and 2 700 cm−1 (β peak), along with
a strong absorption edge rising around 9000 cm−1 (γ peak). Significantly, the temperature-dependent changes
in these peaks show noticeable anomalies across the AFM transition, particularly the emergence of the α peak
and an unusual redshift of the γ peak, suggesting a strong interaction between the charge excitations and the
AFM order. Band-structure calculations reveal that these anomalies arise from magnetization-induced band
renormalizations, including shifts and foldings. Additionally, both phonon modes feature asymmetric Fano line
shapes at low temperatures, with the 95 cm−1 phonon mode exhibiting strong coupling to the fluctuations of Eu
spins. These findings highlight a complex interplay of spin, charge, and lattice degrees of freedom in EuZn2As2.
- Faculty
- Faculté des sciences et de médecine
- Department
- Département de Physique
- Language
-
- English
- Classification
- Physics
- License
-
Rights reserved
- Open access status
- green
- Identifiers
-
- DOI 10.1103/PhysRevB.111.155131
- ISSN 2469-9950
- Persistent URL
- https://folia.unifr.ch/unifr/documents/333364
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