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Engineering a Correlated Narrow-Gap Semiconductor: Effects of Ga Substitution in EuZn$_2$P$_2$

Materials Science 2025-12-22 v1

Abstract

The effect of Ga substitution on the electronic, magnetic, and low-energy responses of the Zintl phase EuZn2_2P2_2 is investigated by electrical transport, electron spin resonance (ESR), and terahertz time-domain spectroscopy (THz-TDS). Incorporating Ga into EuZn2_2P2_2 (EuZn1.8_{1.8}Ga0.2_{0.2}P2_2) reduces the electrical resistivity, indicating enhanced free-carrier density and a narrowed semiconducting gap. ESR confirms the persistence of Eu2+^{2+} moments while showing a crossover from a Lorentzian to a Dysonian lineshape, consistent with reduced skin depth, increased carrier density, and the emergence of diffusive contributions. Ga-substituted compound display pronounced negative magnetoresistance linked to magnetic-polaron formation. THz-TDS reveals strong low-frequency absorption and a notable enhancement of the Drude conductivity in the substituted material, together with an increased carrier scattering time and enhanced carrier-density--to--effective-mass ratio. These results demonstrate that Ga substitution tunes charge transport, carrier dynamics, and short-range magnetic correlations in EuZn2_2P2_2, establishing EuZn1.8_{1.8}Ga0.2_{0.2}P2_2 as a promising platform for engineering correlated narrow-gap magnetic semiconductors with enhanced electronic and spin-dependent functionalities.

Keywords

Cite

@article{arxiv.2512.17123,
  title  = {Engineering a Correlated Narrow-Gap Semiconductor: Effects of Ga Substitution in EuZn$_2$P$_2$},
  author = {M. Dutra and E. Marulanda and G. G. Vasques and J. F. Oliveira and P. C. Sabino and R. B. Delgado and L. Mendonça-Fereira and A. R. V. Benvenho and E. Baggio-Saitovitch and R. K. Machado and N. M. Kawahala and J. Munevar and M. A. Avila and F. G. G. Hernandez},
  journal= {arXiv preprint arXiv:2512.17123},
  year   = {2025}
}

Comments

16 pages, 9 figures