| 报告题目 | Itinerancy enhanced quantum fluctuation of magnetic moments and bimagnon excitations in iron-based superconductors |
| 报告人 | Prof.YAO Daoxin |
| 报告人单位 | Sun Yat-Sen University |
| 报告时间 | 2014-04-18 |
| 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 |
| 报告介绍 | Abstract:
First, I will introduce the itinerancy enhanced quantum fluctuation of magnetic moments in iron-based superconductors. We demonstrate the active role of electron itinerancy in modulating strong anisotropic quantum spatial fluctuation and tuning the ordered anti-ferromagnetic moments. This is performed by first integrating out the itinerant degree of freedom of a degenerate spin-fermion model with Hund's coupling, followed by estimation of quantum fluctuation via spin-wave theory. Our results complement current emphasis on the temporal fluctuation in the literature, and highlight the essential interplay between itinerant and local degree of freedoms. Second, I will talk about the bimagnon excitations in the spatially frustrated Jx?Jy?J2 Heisenberg model on a square lattice in both the antiferromagnetic and the collinear antiferromagnetic phase. Based on an interacting spin wave theory study, we find the appearance of a robust two-peak structure over a wide range of the transferred momenta in both magnetically ordered phases. The unfrustrated model has a single-peak structure with a two-peak splitting originating due to spatial anisotropy and frustrated interactions. Our predicted two-peak structure can be realized in iron pnictides. |
