تقرير
Soft-phonon and charge-density-wave formation in nematic BaNi$_2$As$_2$
| العنوان: | Soft-phonon and charge-density-wave formation in nematic BaNi$_2$As$_2$ |
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| المؤلفون: | Souliou, S. M., Lacmann, T., Heid, R., Meingast, C., Frachet, M., Paolasini, L., Haghighirad, A. -A., Merz, M., Bosak, A., Tacon, M. Le |
| سنة النشر: | 2022 |
| المجموعة: | Condensed Matter |
| مصطلحات موضوعية: | Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Superconductivity |
| الوصف: | We use diffuse and inelastic x-ray scattering to study the formation of an incommensurate charge-density-wave (I-CDW) in BaNi$_2$As$_2$, a candidate system for charge-driven electronic nematicity. Intense diffuse scattering is observed around the modulation vector of the I-CDW, $Q_{I-CDW}$. It is already visible at room temperature and collapses into superstructure reflections in the long-range ordered state where a small orthorhombic distortion occurs. A clear dip in the dispersion of a low-energy transverse optical phonon mode is observed around $Q_{I-CDW}$. The phonon continuously softens upon cooling, ultimately driving the transition to the I-CDW state. The transverse character of the soft-phonon branch elucidates the complex pattern of the I-CDW satellites observed in the current and earlier studies and settles the debated unidirectional nature of the I-CDW. The phonon instability and its reciprocal space position is well captured by our ${ab}$ ${initio}$ calculations. These however indicate that neither Fermi surface nesting, nor enhanced momentum-dependent electron-phonon coupling can account for the I-CDW formation, demonstrating its unconventional nature.% and suggest alternative origins of the I-CDW. Comment: Revised version - to appear in PRL |
| نوع الوثيقة: | Working Paper |
| DOI: | 10.1103/PhysRevLett.129.247602 |
| URL الوصول: | http://arxiv.org/abs/2207.07191 |
| رقم الأكسشن: | edsarx.2207.07191 |
| قاعدة البيانات: | arXiv |
| DOI: | 10.1103/PhysRevLett.129.247602 |
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