Anomalous Pressure Dependence of the Charge Density Wave and Fermi Surface Reconstruction in BaFe<sub>2</sub>Al<sub>9</sub>
<p dir="ltr">We investigate the pressure evolution of charge density wave (CDW) order in the intermetallic compound BaFe<sub>2</sub>Al<sub>9,</sub> which undergoes a pronounced first-order CDW transition ∼1 1 2 K at ambient pressure. High-pressure electrical r...
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| مؤلفون آخرون: | , , , , , , , , , , , , , , |
| منشور في: |
2025
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| الملخص: | <p dir="ltr">We investigate the pressure evolution of charge density wave (CDW) order in the intermetallic compound BaFe<sub>2</sub>Al<sub>9,</sub> which undergoes a pronounced first-order CDW transition ∼1 1 2 K at ambient pressure. High-pressure electrical resistivity and magnetization measurements reveal a systematic enhancement of the CDW transition temperature (T<sub>CDW</sub>) at a rate of ∼60 K / GPa, reaching 300 K under ∼3.2 GPa. The transition sharpness diminishes with pressure, indicating a crossover from first- to second-order behavior. Fermi liquid (FL) fits to the low-temperature resistivity reveal an increase in residual resistivity and a nonmonotonic evolution of the FL coefficient, indicating a pressure-induced Fermi surface (FS) reconstruction. Synchrotron x-ray diffraction reveals anisotropic lattice compression, a change in the compression trend of lattice parameters, and an abrupt change in microstrain at ∼3.6 GPa. Density functional theory calculations reveal pressure-induced flattening of quasi-two-dimensional FS sheets associated with the CDW nesting vector, consistent with enhanced nesting. These findings highlight the critical role of lattice strain and electronic structure evolution in stabilizing a high-temperature CDW phase, making BaFe<sub>2</sub>Al<sub>9</sub> a rare example of a three-dimensional material where pressure promotes rather than suppresses the CDW order.</p><h2 dir="ltr">Other Information</h2><p dir="ltr">Published in: Physical Review Letters<br>License: <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">https://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1103/dxzf-fx8k" target="_blank">https://dx.doi.org/10.1103/dxzf-fx8k</a></p> |
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