Two Routes from Mott Insulators to Metals: Dynamics of Correlated Charge Carriers

从莫特绝缘体到金属的两条途径：相关电荷载流子的动力学

• 批准号: 200045292
• 负责人: Professor Dr. Martin Dressel
• 金额: --
• 依托单位: 1. Physikalisches Institut
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2012
• 资助国家: 德国
• 起止时间: 2011-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/200045292?language=en
• 关键词: Two; Routes; Mott; Insulators; Metals

The project aims at the understanding of the metallic quantum fluctuations in the vicinity of the first-order Mott insulator-to-metal transition. For a fully frustrated model, theoretical calculations yield a coexistence region of metallic and insulating solutions; only very recently we could reveal the first indications of these metallic fluctuations. In the insulating state of quantum spin liquids, the dynamical conductivity becomes significantly enhanced as the temperature is reduced T = 0 K. In this project we suggest to investigate quantum spin liquids as the primary model system with no magnetic order observed down to lowest temperatures. These Mott insulators can be tuned across the phase boundary from the insulator to the metal by varying the effective correlations U/W via increase of the bandwidth W. Here we want to utilize two routes: chemical substitution and hydrostatic pressure.• We want to study the temperature dependence of the (semi-)metallic properties. We want to characterize the metallic fluctuations and see a crossover from quantum fluctuations to thermally driven fluctuations as temperature increases. We have to separate classical percolation effects from quantum-mechanical correlation effects in this coexistence regime.• We want to study the dynamics of these metallic fluctuations by looking at the frequency-dependent conductivity. We search for power laws and their temperature and correlation dependence, as well as for scaling laws.• We want to measure the enhancement of the effective mass in the Fermi liquid regime as the metal-to-insulator transition is approached and compare it with Brinkman-Rice picture.• The bandwidth tuning across the Mott transition will be done by chemical substitution and physical pressure. This implies targeted synthesis and crystal growth on the one hand, pressure-dependent transport and optical experiments on the other hand. • The focus will be on organic charge-transfer salts which constitute quantum spin liquids due to strong frustration on a triangular lattice; supplemented by inorganic systems on kagome and honeycomb lattices.

该项目旨在了解一阶莫特绝缘体到金属转变附近的金属量子涨落，对于完全受抑模型，理论计算直到最近我们才能得出金属和绝缘解决方案的共存区域；揭示了这些金属涨落的第一个迹象，在量子自旋液体的绝缘状态下，随着温度降低 T = 0 K，动态电导率显着增强。在这个项目中，我们建议以量子自旋液体为主要研究对象。在最低温度下没有观察到磁序的模型系统，可以通过增加带宽 W 来改变有效相关性 U/W，从而在从绝缘体到金属的相界上调节这些莫特绝缘体。 ：化学取代和静水压力。• 我们想要研究（半）金属特性的温度依赖性。我们想要表征金属涨落，并随着温度的升高看到从量子涨落到热驱动涨落的交叉。古典这种共存状态下量子力学相关效应的渗流效应。•我们希望通过观察频率相关的电导率来研究这些金属涨落的动力学，我们寻找幂律及其温度和相关性依赖性，以及缩放比例。定律。• 我们想要测量随着金属到绝缘体转变的接近，费米液体状态中有效质量的增强，并将其与布林克曼-赖斯图进行比较。• 莫特转变的带宽调谐将通过化学来完成替代与替代一方面，这意味着有针对性的合成和晶体生长，另一方面，压力相关的传输和光学实验将重点放在由于三角形上的强烈挫败而构成量子自旋液体的有机电荷转移盐上。格子；由戈薇和蜂窝格子上的无机系统补充。