中国科学院合肥物质科学研究院强磁场科学中心坐落于安徽省合肥市风景秀丽的科学岛,2008年4月30日经中国科学院批准成立,依托中国科学院合肥物质科学研究院管理(科发人教字〔2008〕133号),其前身是2005年12月20日成立的“合肥强磁场科学技术研究中心”。中心目标:发展强磁... 更多简介 +
稳态强磁场实验装置(Steady High Magnetic Field Facility,简称SHMFF)是国家发改委支持的“十一五”国家重大科技基础设施。SHMFF法人单位是中国科学院合肥物质科学研究院,共建单位是中国科学技术大学。各项任务以中国科学院强磁场科学中心为依托完成... 更多简介 +
盛志高老师课题组邀请了英国圣安德鲁斯大学严智明博士访问中心并作学术报告,欢迎大家参加,请感兴趣的老师同学相互转告!
时间:5月19日(周五)上午10:00
地点:磁体装备厅203会议室
报告题目:Visualizing polarons on a metal oxide surface and Spin-split surface states at the twin boundaries of non-centrosymmetric BiPd
报告摘要:
In this talk, I will first present my work on studying the behavior of electron small polarons at rutile TiO2(110). Then, I will present my study of the surface electronic structure of non-centrosymmetric BiPd.
Polarons in metal oxides play a crucial role in processes such as catalysis, high Tc superconductivity, and dielectric breakdown in nano-electronics. Using low temperature STM in combination with density functional theory, we study the behavior of electron small polarons associated with oxygen vacancies (VO) at rutile TiO2(110). We observe that the electrons are symmetrically distributed around isolated VO at 78 K, but as the temperature is reduced, their distributions become increasing asymmetric, confirming their polaronic nature. By manipulating isolated VO with the STM tip, we show that particular configurations of polarons are preferred for given locations of the vacancies, which we ascribe to small residual electric fields in the surface. We also form a series of VO-complexes and study their associated electronic distribution.
In non-magnetic bulk materials lacking inversion symmetry, spin-orbit interactions can lift the spin degeneracy, resulting in Rashba metals whose Fermi surfaces exhibit an intricate spin texture. Using scanning tunneling spectroscopy (STS), we study the surface electronic structure in the superconducting state of BiPd, previously reported to exhibit a Dirac-like surface state with a non-trivial spin texture. In STM, both domains of (0-10) and (010) terminations of the crystal structure are present, and separated by twin boundaries (TB). By performing STS, we find that the electronic structure of these non-equivalent domains are characterised by a surface state peak at ~0.4 eV above the Fermi level, and slightly distinct from one another. Intriguingly, we find an additional bound state localized at the TB, the energy of which depends on its orientation at the surface.
报告人简介:
严智明博士,2012年毕业于英国伦敦大学学院化学系,获博士学位,导师Geoff Thornton教授。2012 年 ~ 2016 年,继续于Thornton组从事其对金属氧化物的表面研究。现于英国圣安德鲁斯大学物理系Peter Wahl 组担任博士后研究员,主攻超低温扫描隧道显微镜,研究方向包括:非中心对称超导材料,铁基超导体,自旋阀系统等。以第一作者在PNAS和PRL等期刊上发表多篇论文。
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