| 报告题目 | Pseudospin order in 2D Dirac materials: the role of short vs long-range interactions |
| 报告人 | Dr.JUNG Jeil |
| 报告人单位 | Graphene Research Centre and Department of Physics, National University of Singapore |
| 报告时间 | 2014-10-17 |
| 报告地点 | 合肥微尺度物质科学国家实验室九楼会议室 |
| 主办单位 | 合肥微尺度物质科学国家实验室、国际功能材料量子设计中心、中国科学技术大学物理系 |
| 报告介绍 | Abstract：
The advent of a new class of 2D Dirac materials, among which graphene is a paradigmatic example, has opened up a new frontier in materials research. Their reduced dimensionality makes these systems especially susceptible to electron-electron interactions and their simple stoichiometry makes them ideal platforms to explore in detail the complex role of many-body effects in configuring ordered phases. In this presentation I will use the example of single and few layers graphene to illustrate the role of short vs long-range electron-electron interactions in defining the ground-state properties in Dirac materials, where (layer/valley/spin) pseudospin order and band gap enhancements can take place. Whereas short-range interactions that favor antiferromagnetic spin order can explain a number of experimental observations in zero and finite field Hall measurements, the non-locality of long-ranged interactions can lead to a competition between ground-states exhibiting spontaneous orbital moments that should be tunable through external system parameters and distinguished through transport and spectroscopy measurements.
[1] Theory of the magnetic-field-induced insulator in neutral graphene sheets, J. Jung, A. H. MacDonald, Physical Review B 80 (23), 235417 (2009).
[2] Lattice theory of pseudospin ferromagnetism in bilayer graphene: Competing interaction-induced quantum Hall states, J. Jung, F. Zhang, A. H. MacDonald, Physical Review B 83 (11), 115408 (2011).
[3] Spontaneous quantum Hall states in chirally stacked stacked few-layer graphene systems, J. Jung, G. A. Fiete, Q. Niu, A. H. MacDonald, Physical Review Letters 106 (15), 156801 (2011).
[4] Pseudospin order in monolayer, bilayer and double-layer graphene, A. H. MacDonald, J. Jung, F. Zhang, Physica Scripta 2012 (T146), 014012 (2012).
[5] Gapped broken symmetry states in ABC-stacked trilayer graphene, J. Jung, A. H. MacDonald, Physical Review B 88 (7), 075408 (2013). |
