论文标题
飞秒激光驱动的单层NBSE2的实时TDDFT研究
A real-time TDDFT study of femtosecond laser driven monolayer NbSe2
论文作者
论文摘要
高谐波产生（HHG）光谱有潜力显示凝分物质中有序相的新型特征。我们使用最先进的计算方法研究了单层NBSE2的飞秒激光驱动的电子响应，该方法可以指导未来的合成和光学表征。较早的研究发现，在NBSE2单层的基础状态下，电荷密度波（CDW）有序相位的不同特征与超导性共存。使用超短激光脉冲驱动此类系统可以在单层NBSE2中光学控制各种外来相（例如CDW）的光学上发明新的灯光。这不仅将提供对NBSE2中非平衡相变的基本理解，而且还将为革命量化量子信息技术（例如valleytronics）打开前进的道路。为此，我们研究了使用实时时间依赖性密度功能理论（RT-TDDFT）在各种光泵强度下单层NBSE2中的高谐波产生（HHG）。我们的计算预测了单层NBSE2中CDW顺序存在某些谐波的HHG光谱中的不同特征。最后，我们还检查了HHG光谱对激发强度的依赖性，并定性地揭示了其幂律行为。
High harmonic generation (HHG) spectra have the potential to show novel signatures of ordered phases in condensed matter. We studied the femtosecond laser-driven electronic response of monolayer NbSe2 using state-of-the-art computational methods, which can guide future synthesis and optical characterization. Earlier studies found distinct signatures of charge density wave (CDW) ordered phases in the ground state of NbSe2 monolayers, in co-existence with superconductivity. Driving such systems with ultrashort laser pulses can shed new light on optically controlling various exotic phases (e.g. CDW) in monolayer NbSe2. This will not only provide a fundamental understanding of non-equilibrium phase-transitions in NbSe2, but also will open a path forward for revolutionizing quantum information technologies, such as valleytronics. To this end, we have studied high harmonic generation (HHG) in monolayer NbSe2 under various optical pump intensities using real-time time-dependent density functional theory (RT-TDDFT). Our calculations predict distinct signatures in HHG spectra for certain harmonics in the presence of CDW order in monolayer NbSe2. Finally, we also examined the dependence of HHG spectra on excitation intensity and qualitatively revealed its power-law behavior.
