Guorong LiSend a message to

Guorong Li

Guorong Li

6月6日，美国路易斯安那州立大学Ward Plummer教授受强磁场科学论坛的邀请，访问强磁场科学中心，并作了题为 “Surface and bulk properties of BaMnSb2, a topological semimetal with non-trivial Berry phase (一种具有非平庸贝里相位的拓扑半金属：BaMnSb2,表面和体性质) ”的报告，吸引了来自研究院多个单位的师生积极参加。 尽管拓扑的概念在将近一个世纪之前就已经由狄拉克和外尔提出，但是在拓扑材料中研究具有狄拉克或者外尔费米子的拓扑半金属的工作才刚刚起步。狄拉克或者外尔费米子应该没有有效质量，同时具有极高的迁移率和非平庸的贝利相位，这使得它们具有很大的应用潜力。Ward Plummer教授介绍了具有磁性的半金属材料 BaMnSb2，通过分析在该材料中观察到的量子振荡现象，他们得出该材料具有较小的有效电子质量、较高的迁移率和非平庸的贝利相位。BaMnSb2具有ab面的铁磁和c方向的反铁磁的磁结构，由于磁性打破时间反演对称，所以该材料被认为是一种外尔半金属。理论研究认为，在磁场或者压力下，该材料可能是第二类外尔半金属。通过LEED和STM/STS的研究还发现BaMnSb2具有半导体的表面态。 Plummer 教授是凝聚态物理领域知名学者，于1968年在美国康奈尔大学获得物理学博士学位，现担任美国路易斯安那州立大学教授。Plummer 教授是美国科学院院士，美国艺术与科学院(AAAS)院士。迄今发表学术文章400余篇，是1000位被引用最多的物理学家之一。获得过多项奖励，如原子与表面物理Davission-Germer Prize (1983)、Medard W. Welch Award (2001) 和中国科学院国际科技合作奖 (2016)。

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Guorong LiSend a message to

Guorong Li

Guorong Li

Plummer received a Bachelor of Arts degree from Lewis and Clark College in 1962 and completed his Ph.D. degree in physics at Cornell University in 1967, working with Prof. Thor Rhodin.[2][5] His thesis work was on atomic binding of 5-d transition-metal atoms using Field ion microscope (FIM). Plummer accepted a National Research Council Postdoctoral Fellowship at the National Bureau of Standards [now called The National Institute of Standards and Technology (NIST)] in the fall of 1967 working with Russ Young, and he stayed as a staff scientist until the fall of 1973.[2] His work included field electron emission and photoemission studies of surfaces. NIST selected his 1969 paper "Resonance Tunneling of Field-Emitted Electrons Through Adsorbates on Metal Surfaces", co-authored with J. W. Gadzuk and R. D. Young, for inclusion in the agency's centennial collection of its top 100 articles of the 20th century. This paper reported the first-ever single electron spectroscopy work in which electronic energy levels of atoms at the surface of a metal were observed. In 1973, Plummer accepted a position in the Physics Department at the University of Pennsylvania [2][6] where his work mainly focused on angle-resolved photoemission, momentum-resolved inelastic electron scattering and nonlinear optical response from surfaces. In 1988, he was appointed the William Smith Professor of Physics and in 1990 became the director of the NSF-funded Materials Research Laboratory (Laboratory for Research on Structure of Matter).[2] In January 1993, Plummer moved to a joint position at The University of Tennessee, Knoxville, and Oak Ridge National Laboratory.[2] His research interests shifted to the study on an atomic scale of phase transitions in reduced dimensionality and surfaces of highly correlated electron systems such as transition-metal oxides. His primary research tool was variable-temperature scanning tunneling microscopy. In 2000, Plummer became the Director of the Tennessee Advanced Materials Laboratory, a state-funded Center of Excellence.[2] Plummer served on many national and international committees both to review existing scientific programs and to identify future directions for science and technology. Recent examples include: Chair of DOE-sponsored Workshop on "Soft X-Ray Science in the Next Millennium: The Future of Photon-In/Photon-Out Experiments, Pikeville, Tennessee, March 15–18, 2000, and Chair of DOE-BESAC (Basic Energy Sciences Advisory Committee) subpanel for the evaluation of the Intense Pulsed Neutron Source (IPNS) at Argonne National Laboratory and the Los Alamos Neutron Science Center (LANSCE) Manuel Lujan Jr. Neutron Scattering Center.[2] He also was a member of the DOE-Basic Energy Sciences Advisory Committee, 2001–2004.[2] He was the author of more than 400 refereed papers[1] and included in the list of the 1,000 Most Cited Physicists, a list compiled by the Institute for Scientific Information which is based on papers published between 1981 and 1997. But what Plummer was proudest of in his long and distinguished career was the mentoring of promising young scientists. This included advising or co-advising Ph.D. theses of 40 graduate students, hosting ~25 postdoctoral fellows, and assisting many young scientists in advancing their careers.

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Guorong LiSend a message to

Guorong Li

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