通过工程化飞秒波形驱动的MXenes中相干太赫兹发射的量子流体动力学框架
Quantum Hydrodynamic Framework of Coherent Terahertz Emission in MXenes Driven via Engineered Femtosecond Waveforms
- University of Tehran（德黑兰大学）
- Southern University of Science and Technology（南方科技大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文开发了一种多尺度密度矩阵理论，结合紧束缚哈密顿量与Redfield主方程，揭示了MXenes中相干太赫兹发射的微观机制，为增强宽带太赫兹产生提供了设计策略。
AI中文摘要：
基于低维量子材料的相干太赫兹（THz）发射器在紧凑型宽带光子技术领域已引起广泛关注。然而，对于MXenes而言，能够将微观量子动力学与发射的THz辐射始终关联起来的理论描述仍然有限，MXenes的电子特性由过渡金属d轨道和化学可调的表面终止条件所决定。本文开发了一种多尺度密度矩阵形式理论，用于描述由工程化三色飞秒波形驱动的金属MXenes中相干THz的产生。该理论中，材料特异性电子结构由参数化的多带紧束缚哈密顿量描述，而超快载流子动力学则采用非久期Redfield主方程处理，该方程明确保留了带间相干性、载流子布居、电子-声子相互作用、杂质散射以及环境诱导的弛豫过程。瞬态光电流被明确分解为布居驱动和相干驱动的贡献，并通过其时间导数与发射的THz场关联起来，建立了微观量子动力学与宏观辐射之间的直接联系。研究结果表明，环境耦合不仅会衰减THz发射，还会重新分配相干电流和布居电流，并在时域和频域中重塑发射的波形。对光波形参数、有效电子结构和开放系统弛豫的系统研究，确定了增强宽带THz产生的物理基础策略。本文提出的方法建立了一个可转移的微观设计平台，用于关联MXenes及相关低维量子材料的材料特异性电子结构、量子相干性、开放系统弛豫、非线性载流子输运以及相干THz发射。
英文摘要：
Coherent terahertz (THz) emitters based on low dimensional quantum materials have attracted significant interest for compact broadband photonic technologies. However, theoretical descriptions that consistently connect microscopic quantum dynamics to emitted THz radiation remain limited for MXenes, whose electronic properties are governed by transition metal d orbitals and chemically tunable surface terminations. A multiscale density-matrix formalism for coherent THz generation in metallic MXenes driven by engineered three color femtosecond waveforms is developed. Material-specific electronic structures are described by parameterized multiband tight binding Hamiltonians, while ultrafast carrier dynamics are treated using a non-secular Redfield master equation that explicitly retains interband coherence, carrier populations, electron phonon interactions, impurity scattering, and environment-induced relaxation. The transient photocurrent is explicitly decomposed into population and coherence driven contributions and linked to the emitted THz field through its time derivative, establishing a direct connection between microscopic quantum dynamics and macroscopic radiation. The results show that environmental coupling does not merely attenuate THz emission, but redistributes coherent and population currents and reshapes the emitted waveform in both the time and frequency domains. Systematic investigations of optical waveform parameters, effective electronic structure, and open system relaxation identify physically grounded strategies for enhancing broadband THz generation. The proposed methodology establishes a transferable microscopic design platform for connecting material specific electronic structure, quantum coherence, open system relaxation, nonlinear carrier transport, and coherent THz emission across MXenes and related low dimensional quantum materials.
