[NCTS Physics Research Highlights] Yang-hao Chan 'Giant self-driven exciton-Floquet signatures in time-resolved photoemission spectroscopy of MoS2 from time-dependent GW approach', PNAS 120, e2301957120 (2023)

• 2023-11-24
• Chen, Jhan Yu 陳詹喻
• Computational quantum materials Condensed Matter

Giant self-driven exciton-Floquet signatures in time-resolved photoemission spectroscopy of MoS2 from time-dependent GW approach
時依GW方法模擬在二硫化鉬光電子能譜中的自驅激子-弗洛凱特徵

Y.-H. Chan*, Diana Y. Qiu, Felipe H. da Jornada, and Steven G. Louie
PNAS 120, e2301957120 (2023)
DOI: https://www.pnas.org/doi/10.1073/pnas.2301957120

Engineering material properties through coherent optical fields has led to the discovery of light-induced transient superconductivity, ferroelectric transitions, and other exotic phases, which were previously thought to exist only in equilibrium. Here, we show that materials’ electronic structure can also be engineered with a “self-driven exciton-Floquet effect,” where the pump light creates excitons with a coherent polarization that itself acts as a driving field, independent of the light field. We demonstrate such effects in monolayer MoS2 from first-principles calculations and show that it can provide an understanding to modify the material’s band structure in time-resolved angle-resolved photoemission experiments.

研究發現透過同調光場調控材料可以產生光致瞬態超導、鐵電轉變和其他奇異相，這些相以前被認為只存在於平衡狀態。我們展示了也可以透過「自驅動激子-弗洛凱效應」調控材料的電子結構。由光激發產生獨立於光外場具有同調性的激子其本身能充當驅動場。我們透過第一原理計算展示在單層二硫化鉬中的這種效應，以及它如何幫助理解在時間分辨角分辨光電子實驗中測得的能帶結構改變。