Elastocaloric evidence for a multicomponent superconductor stabilized within the nematic state in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$
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| Main Authors: | , , , , , , , , , , , , , , |
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| Format: | Preprint |
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2024
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| author | Ghosh, Sayak Ikeda, Matthias S. Chakraborty, Anzumaan R. Worasaran, Thanapat Theuss, Florian Peralta, Luciano B. Lozano, P. M. Kim, Jong-Woo Ryan, Philip J. Ye, Linda Kapitulnik, Aharon Kivelson, Steven A. Ramshaw, B. J. Fernandes, Rafael M. Fisher, Ian R. |
| author_facet | Ghosh, Sayak Ikeda, Matthias S. Chakraborty, Anzumaan R. Worasaran, Thanapat Theuss, Florian Peralta, Luciano B. Lozano, P. M. Kim, Jong-Woo Ryan, Philip J. Ye, Linda Kapitulnik, Aharon Kivelson, Steven A. Ramshaw, B. J. Fernandes, Rafael M. Fisher, Ian R. |
| contents | The iron-based high-$T_c$ superconductors exhibit rich phase diagrams with intertwined phases, including magnetism, nematicity and superconductivity. The superconducting $T_c$ in many of these materials is maximized in the regime of strong nematic fluctuations, making the role of nematicity in influencing the superconductivity a topic of intense research. Here, we use the AC elastocaloric effect (ECE) to map out the phase diagram of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ near optimal doping. The ECE signature at $T_c$ on the overdoped side, where superconductivity condenses without any nematic order, is quantitatively consistent with other thermodynamic probes that indicate a single-component superconducting state. In contrast, on the slightly underdoped side, where superconductivity condenses within the nematic phase, ECE reveals a second thermodynamic transition proximate to and below $T_c$. We rule out magnetism and re-entrant tetragonality as the origin of this transition, and find that our observations strongly suggest a phase transition into a multicomponent superconducting state. This implies the existence of a sub-dominant pairing instability that competes strongly with the dominant $s^\pm$ instability. Our results thus motivate a re-examination of the pairing state and its interplay with nematicity in this extensively studied iron-based superconductor, while also demonstrating the power of ECE in uncovering strain-tuned phase diagrams of quantum materials. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2402_17945 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Elastocaloric evidence for a multicomponent superconductor stabilized within the nematic state in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ Ghosh, Sayak Ikeda, Matthias S. Chakraborty, Anzumaan R. Worasaran, Thanapat Theuss, Florian Peralta, Luciano B. Lozano, P. M. Kim, Jong-Woo Ryan, Philip J. Ye, Linda Kapitulnik, Aharon Kivelson, Steven A. Ramshaw, B. J. Fernandes, Rafael M. Fisher, Ian R. Superconductivity Strongly Correlated Electrons The iron-based high-$T_c$ superconductors exhibit rich phase diagrams with intertwined phases, including magnetism, nematicity and superconductivity. The superconducting $T_c$ in many of these materials is maximized in the regime of strong nematic fluctuations, making the role of nematicity in influencing the superconductivity a topic of intense research. Here, we use the AC elastocaloric effect (ECE) to map out the phase diagram of Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ near optimal doping. The ECE signature at $T_c$ on the overdoped side, where superconductivity condenses without any nematic order, is quantitatively consistent with other thermodynamic probes that indicate a single-component superconducting state. In contrast, on the slightly underdoped side, where superconductivity condenses within the nematic phase, ECE reveals a second thermodynamic transition proximate to and below $T_c$. We rule out magnetism and re-entrant tetragonality as the origin of this transition, and find that our observations strongly suggest a phase transition into a multicomponent superconducting state. This implies the existence of a sub-dominant pairing instability that competes strongly with the dominant $s^\pm$ instability. Our results thus motivate a re-examination of the pairing state and its interplay with nematicity in this extensively studied iron-based superconductor, while also demonstrating the power of ECE in uncovering strain-tuned phase diagrams of quantum materials. |
| title | Elastocaloric evidence for a multicomponent superconductor stabilized within the nematic state in Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ |
| topic | Superconductivity Strongly Correlated Electrons |
| url | https://arxiv.org/abs/2402.17945 |