Dielectric disorder in two-dimensional materials
Dielectric disorder in two-dimensional materials
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DOI：
10.1038/s41565-019-0520-0
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发表时间：
2019-09-01
影响因子：
38.3
通讯作者：
Chernikov, Alexey
中科院分区：
文献类型：
--
作者：
Raja, Archana;Waldecker, Lutz;Chernikov, Alexey
理解和控制障碍是纳米技术和材料科学的关键。传统上，疾病归因于固有物质特性的局部波动，例如化学和结构成分，掺杂或应变。在这里，我们提供了纳米级系统中疾病的根本新来源，该来源完全基于由于外部介电环境的波动而导致的库仑相互作用的局部变化。使用二维半导体作为原型，我们通过探测激子共振的统计数据和相关性，通过实验监测介电障碍，理论上分析了外部筛选和声子散射的影响。即使是介电环境的中等波动也被证明会引起带隙和激子结合能的巨大变化，直到100 MEV范围，通常使其成为不均匀性的主要来源。结果，介电障碍对纳米级材料及其异质结构的光学和运输特性都具有很大的影响。
Understanding and controlling disorder is key to nanotechnology and materials science. Traditionally, disorder is attributed to local fluctuations of inherent material properties such as chemical and structural composition, doping or strain. Here, we present a fundamentally new source of disorder in nanoscale systems that is based entirely on the local changes of the Coulomb interaction due to fluctuations of the external dielectric environment. Using two-dimensional semiconductors as prototypes, we experimentally monitor dielectric disorder by probing the statistics and correlations of the exciton resonances, and theoretically analyse the influence of external screening and phonon scattering. Even moderate fluctuations of the dielectric environment are shown to induce large variations of the bandgap and exciton binding energies up to the 100 meV range, often making it a dominant source of inhomogeneities. As a consequence, dielectric disorder has strong implications for both the optical and transport properties of nanoscale materials and their heterostructures.