Direct observation of a uniaxial stress-driven Lifshitz transition in Sr2RuO4
Direct observation of a uniaxial stress-driven Lifshitz transition in Sr2RuO4
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DOI：
10.1038/s41535-019-0185-9
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发表时间：
2019-08-19
影响因子：
5.7
通讯作者：
Mackenzie, Andrew P.
中科院分区：
文献类型：
--
作者：
Sunko, Veronika;Morales, Edgar Abarca;Mackenzie, Andrew P.
压力代表了一个用于遍历相互作用电子系统的复杂相图的干净的调谐参数，因此已被证明在量子材料的研究中至关重要。最近的研究表明，控制单轴压力的应用可以使非常规超导体 Sr2RuO4 的转变温度提高一倍以上，从而导致 T-c 与应变的明显峰值，其起源仍在激烈争论中。在这里，我们开发了一种简单而紧凑的方法，在受限的样品环境中被动施加大的单轴压力，并利用该方法利用角分辨光发射来研究 Sr2RuO4 电子结构的演化。我们直接可视化单轴应力如何驱动 .-band 费米面的 Lifshitz 跃迁，指出将其相关的范霍夫奇点应变调整到费米能级在调节 Tc 峰值中的关键作用。我们的测量为 Sr2RuO4 应变调谐电子结构演化的理论模型提供了严格的约束。更一般地说，我们的实验方法为未来研究应变调谐相变打开了大门，不仅使用光电发射，而且还使用其他实验技术，在这些技术中大型压力电池或基于压电的设备可能难以实现。
Pressure represents a clean tuning parameter for traversing the complex phase diagrams of interacting electron systems, and as such has proved of key importance in the study of quantum materials. Application of controlled uniaxial pressure has recently been shown to more than double the transition temperature of the unconventional superconductor Sr2RuO4, leading to a pronounced peak in T-c versus strain whose origin is still under active debate. Here we develop a simple and compact method to passively apply large uniaxial pressures in restricted sample environments, and utilise this to study the evolution of the electronic structure of Sr2RuO4 using angle-resolved photoemission. We directly visualise how uniaxial stress drives a Lifshitz transition of the.-band Fermi surface, pointing to the key role of strain-tuning its associated van Hove singularity to the Fermi level in mediating the peak in Tc. Our measurements provide stringent constraints for theoretical models of the strain-tuned electronic structure evolution of Sr2RuO4. More generally, our experimental approach opens the door to future studies of strain-tuned phase transitions not only using photoemission but also other experimental techniques where large pressure cells or piezoelectric-based devices may be difficult to implement.