Elastocaloric signature of nematic fluctuations
Elastocaloric signature of nematic fluctuations
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DOI：
10.1073/pnas.2105911118
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发表时间：
2021-09-14
影响因子：
11.1
通讯作者：
Fisher, Ian R.
中科院分区：
文献类型：
--
作者：
Ikeda, Matthias S.;Worasaran, Thanapat;Fisher, Ian R.
弹性热效应（ECE）将熵的变化与材料所经历的应变的变化相关联。因此，ECE测量可以提供关于接近应变调谐相变的熵景观的有价值的信息。对于有序的状态，只打破点对称性，双线性耦合的序参量与应变意味着ECE也可以提供一个窗口的波动以上的临界温度，因此，在原则上，也可以提供一个热力学测量相关的磁化率。为了证明这一点，我们使用的ECE灵敏地揭示了存在的超导体Ba（Fe 1-xCox）2As 2的原型铁基超导体的超导波动。通过同时进行这些测量与弹性电阻率在一个多模态的方式，我们能够作出直接和明确的比较这些密切相关的热力学和输运性质，这两者都是敏感的波动。其结果是，我们已经发现了一个意想不到的掺杂依赖的线弹性耦合和低能量准粒子的散射的幅度由波动，而前者减弱，后者随着掺杂的增加显着增加。
The elastocaloric effect (ECE) relates changes in entropy to changes in strain experienced by a material. As such, ECE measurements can provide valuable information about the entropy landscape proximate to strain-tuned phase transitions. For ordered states that break only point symmetries, bilinear coupling of the order parameter with strain implies that the ECE can also provide a window on fluctuations above the critical temperature and hence, in principle, can also provide a thermodynamic measure of the associated susceptibility. To demonstrate this, we use the ECE to sensitively reveal the presence of nematic fluctuations in the archetypal Fe-based superconductor Ba(Fe1-xCox)2As2. By performing these measurements simultaneously with elastoresistivity in a multimodal fashion, we are able to make a direct and unambiguous comparison of these closely related thermodynamic and transport properties, both of which are sensitive to nematic fluctuations. As a result, we have uncovered an unanticipated doping dependence of the nemato-elastic coupling and of the magnitude of the scattering of low-energy quasi-particles by nematic fluctuations-while the former weakens, the latter increases dramatically with increasing doping.