Langevin dynamics/Monte Carlo simulations method for calculating nanoscale dielectric functions of materials
Langevin dynamics/Monte Carlo simulations method for calculating nanoscale dielectric functions of materials
复制标题
DOI：
10.1103/physrevmaterials.6.076001
复制
发表时间：
2022-07-14
影响因子：
3.4
通讯作者：
Abate, Yohannes
中科院分区：
文献类型：
--
作者：
Hancock, Steven B.;Landau, David P.;Abate, Yohannes
我们已经开发了一种模拟方法来计算纳米级的频率依赖性的复杂的介电函数的范围广泛的材料，使用朗之万动力学和大都会蒙特卡罗方法的组合。这种方案的前提是使用材料的原子结构，并指定适当的原子间相互作用以及内部场耦合来容纳相关材料。我们验证我们的模型，通过重建良好的研究代表性材料，包括绝缘体二氧化硅薄膜，具有声子共振在中红外，和半导体单层二硫化钼，表现出强激子共振在可见光频率范围内的介电函数。为了进一步展示该模型在计算复杂材料的纳米级介电调制的能力，我们模拟了SmNiO 3，相关的钙钛矿氧化物，相对于不同水平的氢化，氧空位形成，和外场的介电响应。这是通过使用大都会蒙特卡罗方法插入和跟踪掺杂剂在纳米尺度上的运动来实现的，该方法明确地包括彼此之间以及外部场的相互作用。模拟纳米介电谱同意非常好的高分辨率近场实验测量的基础上散射型扫描近场显微镜。我们发现，这种建模方案在描述和预测暴露于不断变化的局部环境的各种材料的纳米级介电行为方面具有广泛的实用性。
We have developed a simulational methodology for calculating the nanoscale frequency-dependent complex dielectric function of a wide range of materials using a combination of Langevin dynamics and Metropolis Monte Carlo methods. The premise of such a scheme is to use the atomistic structure of materials and designate appropriate interatomic interactions as well as internal field couplings to accommodate correlated materials. We validate our model by recreating the dielectric functions of well-studied representative materials including insulator SiO2 thin film that has phonon resonances in the midinfrared, and semiconductor monolayer MoS2 that exhibits strong excitonic resonances in the visible frequency range. To further showcase the capability of the model in calculating nanoscale dielectric modulation of complex materials, we simulate the dielectric response of SmNiO3, a correlated perovskite oxide, with respect to differing levels of hydrogenation, oxygen vacancy formation, and external fields. This is accomplished by inserting and tracking the movement of dopants at the nanoscale using Metropolis Monte Carlo methods that explicitly include interactions with each other as well as external fields. Simulated nanoscale dielectric spectra agree very well with high-resolution near-field experimental measurements based on scattering type scanning near-field microscopy. We find that this modeling scheme carries a broad utility in describing and predicting the nanoscale dielectric behavior of a broad range of materials exposed to changing local environments.