Regensburg 2025 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 54: Correlated Electrons: Charge Order
TT 54.1: Vortrag
Freitag, 21. März 2025, 09:30–09:45, H33
Broad-Band Noise at the Different CDW Transitions in BaNi2As2 — •Julian Beu1, Marvin Kopp1, Markus König2, Amir Haghighirad3, Matthieu Le Tacon3, Jure Demsar4, and Jens Müller1 — 1Institute of Physics, Goethe-University Frankfurt, Frankfurt (Main), Germany — 2MPI CPfS, Dresden, Germany — 3KIT, Karlsruhe, Germany — 4Institute of Physics, JGU, Mainz
Ever since collective modes like charge (CDW) and spin density waves (SDW) have been routinely found near to or in direct competition with unconventional superconductivity in many interesting compounds, including high-Tc cuprates and iron-pnictides, the influence of these states on the superconducting phase is of interest. In this work we focus on BaNi2As2 (BNA), a structurally close analogue of the 122-type iron-based superconductors. In contrast to the iron-pnictides, no magnetic ordering was observed in BNA, and two different CDW phases, one incommensurate (I-CDW) and the other commensurate (C-CDW), replace a SDW phase. We investigate the charge carriers in samples of BaNi2(As1−3.5% P3.5%)2 by analyzing the resistance and broad-band noise properties. The samples are structured by a FIB process with a meander current path in order to increase the absolute resistance by two orders of magnitude, making fluctuation spectroscopy possible. Our measurements reveal significant differences in the behavior of the electronic fluctuations at the two CDW formations, that show interesting connections to recent findings regarding the properties of the I-CDW in BNA [1] and our noise measurements performed on the conventional CDW system K0.3MoO3. [1] Phys. Rev. Lett. 129, 247602.
Keywords: CDW; Broad-band noise; Resistance noise spectroscopy; Blue Bronze; BaNi2As2