Evolution of the charge carrier properties and electronic correlations in layered organic metals near the Mott metal-insulator transition

莫特金属-绝缘体转变附近层状有机金属中载流子特性和电子相关性的演变

• 批准号: 449241039
• 负责人: Professor Dr. Rudolf Gross
• 金额: --
• 依托单位: Russian Foundation for Basic Research
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/449241039?language=en
• 关键词: Evolution; charge; carrier; properties; electronic

The Mott transition is one of the most fundamental correlation-driven instabilities in normal metals. Despite extensive studies, there are important unresolved problems and open questions, in particular regarding the experimental study of the metallic ground state in the immediate vicinity of the insulating state in well-defined model systems. Within this project, we join experts from experimental and theoretical physics and materials science to tackle these problems. We will employ kappa-type organic charge transfer salts as quasi-2D electronic model systems with bandwidth-controlled Mott instability for tracking the evolution of key characteristics of the charge carriers in the metal/insulator coexistence region of the phase diagram as well as in the neighboring homogeneous metallic state. In particular, we will study (i) the correlation-induced renormalization of the effective mass, (ii) the exact geometry and topology of the Fermi surface, and (iii) the coherence of charge transport. The systematic study of these characteristics in well-defined model systems will provide a crucial test for the existing theories of the Mott metal-insulator transition.A key objective of the project is the disentanglement of contributions of charge, spin, and lattice degrees of freedom to the metal-insulator instability. This problem will be addressed by studying kappa-type salts with different strength of geometrical frustration, magnetic interactions, and lattice disorder. The salts of BEDT-TTF with different anions are particularly suited for studying the effects of geometrical frustration, while BETS salts with localized magnetic moments give access to the interplay between electronic correlations and magnetic interactions. The coupling of the electronic state to lattice degrees of freedom will be probed by studying the influence of deuteration of BEDT-TTF salts on the charge carrier properties and by tracing the impact of ethylene-group disorder in these salts.The main experimental probes for addressing the above issues will be magnetic quantum oscillations, semiclassical anisotropic magnetotransport, and resistivity anisotropy. A precise control of the electronic ground state with respect to the metal-insulator boundary will be realized by fine-tuning materials with quasi-hydrostatic pressure as well as "chemical pressure". A quantitative analysis of the experimental results will be carried out by the theory team involved in the project using the state-of-the-art theory of high-field magnetotransport in quasi-2D metals as well as of the charge transport in phase-separated electronic media. Further development of the (magneto)transport theory in the segments related to the proposed experiments is planned.The availability of top-quality single crystals of kappa-type salts is crucial for the success of the planned project. The preparation and characterization of such crystals will be carried out by the experienced materials science team of the project.

莫特转变是正常金属中最基本的相关驱动不稳定性之一。尽管广泛的研究，有重要的未解决的问题和开放的问题，特别是关于在良好定义的模型系统中的绝缘状态附近的金属基态的实验研究。在这个项目中，我们加入了实验和理论物理以及材料科学的专家来解决这些问题。我们将使用卡帕型有机电荷转移盐作为具有带宽控制的Mott不稳定性的准二维电子模型系统，用于跟踪相图的金属/绝缘体共存区域以及相邻区域中电荷载流子关键特征的演变。均匀金属状态。特别是，我们将研究（i）相关诱导的重整化的有效质量，（ii）确切的几何形状和拓扑结构的费米面，和（iii）的连贯性的电荷输运。在定义明确的模型系统中系统地研究这些特性将为现有的Mott金属-绝缘体相变理论提供一个重要的检验。该项目的一个关键目标是解开电荷、自旋和晶格自由度对金属-绝缘体不稳定性的贡献。这个问题将通过研究具有不同强度的几何挫折，磁相互作用和晶格无序的卡帕型盐来解决。具有不同阴离子的BEDT-TTF的盐特别适合于研究几何挫折的影响，而具有局部磁矩的BETS盐可以获得电子相关性和磁相互作用之间的相互作用。通过研究BEDT-TTF盐的氘化对电荷载流子性质的影响以及追踪这些盐中乙烯基无序的影响，将探索电子态与晶格自由度的耦合，解决上述问题的主要实验探针将是磁量子振荡，半经典各向异性磁输运和电阻率各向异性。精确控制电子基态相对于金属-绝缘体边界将实现微调材料与准流体静压以及“化学压力”。实验结果的定量分析将由参与该项目的理论团队使用准二维金属中高场磁输运的最新理论以及相分离电子介质中电荷输运的最新理论进行。计划在与拟议的实验有关的部分进一步发展（磁）输运理论，获得高质量的卡帕型盐单晶对计划项目的成功至关重要。这些晶体的制备和表征将由该项目经验丰富的材料科学团队进行。