Ultrafast relaxation of acoustic and optical phonons in a topological nodal-line semimetal ZrSiS
Ultrafast relaxation of acoustic and optical phonons in a topological nodal-line semimetal ZrSiS
复制标题
DOI：
10.1038/s42005-022-00980-6
复制
发表时间：
2021-11
影响因子：
5.5
通讯作者：
Yangyang Liu;Gyanendra Dhakal;Anup Pradhan Sakhya;John E. Beetar;Firoz Kabir;Sabin Regmi;D. Kaczorowski;M. Chini;Benjamin M. Fregoso;M. Neupane
中科院分区：
文献类型：
--
作者：
Yangyang Liu;Gyanendra Dhakal;Anup Pradhan Sakhya;John E. Beetar;Firoz Kabir;Sabin Regmi;D. Kaczorowski;M. Chini;Benjamin M. Fregoso;M. Neupane
最近，基于 ZrSiS 系列的节线半金属引起了广泛的研究兴趣，贡献了大量的实验和理论工作。尽管 ZrSiS 是研究最多的节线半金属，但人们对 ZrSiS 的瞬态弛豫动力学和潜在机制仍缺乏清晰的了解。使用时间和角度分辨光电子能谱，我们研究了 ZrSiS 中的超快弛豫动力学，并揭示了体节线态中的独特弛豫，这是通过基于光学和声学声子冷却的简单模型很好地捕获的。我们的模型预测光学和声学声子弛豫的线性衰减过程，在较高温度下光学冷却占主导地位。我们的结果揭示了体态和表面态的不同衰减机制，并为理解这种材料的传导机制铺平了道路。
Recently, nodal line semimetals based on ZrSiS-family have garnered massive research interests contributing numerous experimental and theoretical works. Despite being the most studied nodal-line semimetal, a clear understanding of the transient state relaxation dynamics and the underlying mechanism in ZrSiS is lacking. Using time- and angle-resolved photoemission spectroscopy, we study the ultrafast relaxation dynamics in ZrSiS and reveal a unique relaxation in the bulk nodal-line state which is well-captured by a simple model based on optical and acoustic phonon cooling. Our model predicts linear decay processes for both optical and acoustic phonon relaxations with optical cooling dominant at higher temperatures. Our results reveal different decay mechanisms for the bulk and surface states and pave a way to understand the mechanism of conduction in this material.