Gippius, A. A.; Zhurenko, S. V.; Tkachev, A. V.; Gunbin, A. V.; Büttgen, N.; Schaedler, M.; Silkin, I. G.; Morozov, I. V.; Bogach, A. V.; Sobolev, A. V.; Presniakov, I. A.; Moskvin, A. S. Short-range helical magnetic order in FeP1-xAsx (x = 0.33 and 0.5) Journal Article J. Magn. Magn. Mater. 651, 174177 (2026). @article{GIPPIUS2026174177,
title = {Short-range helical magnetic order in FeP_{1-x}As_{x} (x = 0.33 and 0.5)},
author = {A. A. Gippius and S. V. Zhurenko and A. V. Tkachev and A. V. Gunbin and N. Büttgen and M. Schaedler and I. G. Silkin and I. V. Morozov and A. V. Bogach and A. V. Sobolev and I. A. Presniakov and A. S. Moskvin},
url = {https://www.sciencedirect.com/science/article/pii/S0304885326003689},
doi = {10.1016/j.jmmm.2026.174177},
year = {2026},
date = {2026-08-01},
urldate = {2026-08-01},
journal = {J. Magn. Magn. Mater.},
volume = {651},
pages = {174177},
abstract = {Although the FeP1-xAsx solid solution compounds are isostructural with the binary helimagnets FeP and FeAs with MnP-type structure (sp. gr. Pnma) of the B31 family, their magnetic structure remained unclear. We studied two members of this family (x = 0.33 and 0.5) via microscopic site-selective techniques such as Mössbauer and NMR spectroscopy. Our results indicate that the helimagnetic nature of the ground state is preserved, but undergoes significant modifications. In particular, its ordering range seems to become drastically shorter, so that the local fields on the non-magnetic phosphorus atoms decrease several times compared to those in FeP, and even local fields on iron slightly decrease compared to FeP and FeAs. The ordering temperature for these fragmented structures is suppressed down to 20–30 K, which is significantly lower than the TN values for FeP and FeAs. Additionally, both compounds demonstrate higher sustainability to the external field than the parent compound FeP.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Although the FeP1-xAsx solid solution compounds are isostructural with the binary helimagnets FeP and FeAs with MnP-type structure (sp. gr. Pnma) of the B31 family, their magnetic structure remained unclear. We studied two members of this family (x = 0.33 and 0.5) via microscopic site-selective techniques such as Mössbauer and NMR spectroscopy. Our results indicate that the helimagnetic nature of the ground state is preserved, but undergoes significant modifications. In particular, its ordering range seems to become drastically shorter, so that the local fields on the non-magnetic phosphorus atoms decrease several times compared to those in FeP, and even local fields on iron slightly decrease compared to FeP and FeAs. The ordering temperature for these fragmented structures is suppressed down to 20–30 K, which is significantly lower than the TN values for FeP and FeAs. Additionally, both compounds demonstrate higher sustainability to the external field than the parent compound FeP. |
Hemmida, M.; Pakhira, S.; Johnston, D. C.; von Nidda, H. -A. Krug Observation of surface ferromagnons in the axion-insulating phase of the antiferromagnetic topological insulator EuSn2As2 Journal Article Phys. Rev. Research 8, 023309 (2026). @article{dp4g-dyll,
title = {Observation of surface ferromagnons in the axion-insulating phase of the antiferromagnetic topological insulator EuSn_{2}As_{2}},
author = {M. Hemmida and S. Pakhira and D. C. Johnston and H. -A. Krug von Nidda},
url = {https://link.aps.org/doi/10.1103/dp4g-dyll},
doi = {10.1103/dp4g-dyll},
year = {2026},
date = {2026-06-17},
urldate = {2026-06-01},
journal = {Phys. Rev. Research},
volume = {8},
number = {2},
pages = {023309},
abstract = {We report the study of spin dynamics of Eu2+ in the antiferromagnetic axion topological insulator EuSn2As2 by means of antiferromagnetic resonance at 9.34 GHz. Below the Néel temperature (T_N), two types of resonance modes, the conventional bulk antiferromagnetic resonance and additional surface ferromagnetic resonance, are observed. The latter turns out to be characteristic of the axion-insulating phase. Above T_N, we prove the existence of a Kosterlitz-Thouless scenario that is relevant for the spin relaxation in the Eu2+ layers. The absence of Korringa relaxation indicates the strong confinement of the conduction electrons at the Fermi level to the SnAs layers.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
We report the study of spin dynamics of Eu2+ in the antiferromagnetic axion topological insulator EuSn2As2 by means of antiferromagnetic resonance at 9.34 GHz. Below the Néel temperature (T_N), two types of resonance modes, the conventional bulk antiferromagnetic resonance and additional surface ferromagnetic resonance, are observed. The latter turns out to be characteristic of the axion-insulating phase. Above T_N, we prove the existence of a Kosterlitz-Thouless scenario that is relevant for the spin relaxation in the Eu2+ layers. The absence of Korringa relaxation indicates the strong confinement of the conduction electrons at the Fermi level to the SnAs layers. |
Lamp, M.; Ebad-Allah, J.; Chmeruk, A.; Bura, N.; Schönemann, R.; Balicas, L.; Lee, S. H.; Mao, Z. Q.; Chioncel, L.; Kuntscher, C. A. Charge dynamics in the Weyl semimetals NbIrTe4 and TaIrTe4 under pressure: Signatures of an electronic phase transition Unpublished (2026), arXiv:2606.02085. @unpublished{lamp:ChargeDynamics2026,
title = {Charge dynamics in the Weyl semimetals NbIrTe_{4} and TaIrTe_{4} under pressure: Signatures of an electronic phase transition},
author = {M. Lamp and J. Ebad-Allah and A. Chmeruk and N. Bura and R. Schönemann and L. Balicas and S. H. Lee and Z. Q. Mao and L. Chioncel and C. A. Kuntscher},
url = {https://arxiv.org/abs/2606.02085},
doi = {10.48550/arXiv.2606.02085},
year = {2026},
date = {2026-06-01},
urldate = {2026-06-01},
abstract = {A high-pressure investigation of the Weyl semimetals NbIrTe4 and TaIrTe4 is presented, using infrared spectroscopy supplemented by density functional theory calculations. The experimental optical conductivity spectra as a function of pressure suggest the occurrence of a pressure-induced phase transition at a critical pressure P_c = 7-8 GPa. This transition is most likely electronic in nature, as Raman scattering measurements provide no evidence of a significant structural phase transition. Above P_c a significant redistribution of spectral weight occurs in the optical conductivity spectrum for both materials. A Drude-Lorentz analysis of the optical data indicates a sharp reduction in the free carrier concentration at P_c, concomitant with the appearance of a low-energy phonon, which was initially screened by free charge carriers. A predominantly electronic origin of the phase transition is supported by the calculated electronic band structure, Fermi surface, and interband optical conductivity as a function of pressure. Our findings provide collective evidence for a pressure-induced, most likely electronic phase transition in both van der Waals materials at P_c=7-8 GPa, highlighting the tunability of their electronic band structure by hydrostatic pressure.},
note = { arXiv:2606.02085},
keywords = {},
pubstate = {published},
tppubtype = {unpublished}
}
A high-pressure investigation of the Weyl semimetals NbIrTe4 and TaIrTe4 is presented, using infrared spectroscopy supplemented by density functional theory calculations. The experimental optical conductivity spectra as a function of pressure suggest the occurrence of a pressure-induced phase transition at a critical pressure P_c = 7-8 GPa. This transition is most likely electronic in nature, as Raman scattering measurements provide no evidence of a significant structural phase transition. Above P_c a significant redistribution of spectral weight occurs in the optical conductivity spectrum for both materials. A Drude-Lorentz analysis of the optical data indicates a sharp reduction in the free carrier concentration at P_c, concomitant with the appearance of a low-energy phonon, which was initially screened by free charge carriers. A predominantly electronic origin of the phase transition is supported by the calculated electronic band structure, Fermi surface, and interband optical conductivity as a function of pressure. Our findings provide collective evidence for a pressure-induced, most likely electronic phase transition in both van der Waals materials at P_c=7-8 GPa, highlighting the tunability of their electronic band structure by hydrostatic pressure. |
