主讲人：李有泉 教授（浙江大学/南开大学）

题目：Manipulation of Skyrmions and the Promising Applications

时间：2023年08月04日（星期五）上午10：00

地点：理工楼1201报告厅

邀请人：罗洪刚

报告摘要：

There has been spectacular progress in the studyon multiferroics, which is expected to make a realistic step toward an electrical control of magnetism or four state memories. We propose a tilted Heisenberg model of which the continuum limit is a gauge Landau-Lifshitz equation that provides a unified description for various exotic spin orders appeared. For certain gauge potential, we solved the magnetic skyrmion phase and also predicted the emergence of meron phase [1]. We also propose a mechanism to pin skyrmions in chiral magnet [2], and find that the position-dependent electric field can induce the Hall motion of the skyrmion [3]. Furthermore, we study spin-orbital driven ferroelectricity [4]; spin-orbital coupling and charge effect in Mott insulators showing that the tilted Heisenberg model can be derived from the Hubbard model in the presence of spin-orbital coupling as the large U limit [5]. The idea of tilted Heisenberg model has been extended to the SU(3) case by experts working on high-energy physics recently [6]. Moreover, we show that in the stationary regime the chirality of the domain wall can be efficiently reversed when the electric field is applied along the direction of the magnetic field. These characteristics suggest that the multiferroic domain wall may provide a new prospective means to design faster and low-power-consumption domain wall devices [7,8]. These results are expected to motivate experimentalists to prepare new type of multiferroics material or design new spintronics device [9-11].

References

[1] Y. Q. Li, Y. H. Liu, and Y. Zhou, General spin order theory via gauge Landau- Lifshitz equation, Phys. Rev. B. 84, (2011) 205123;

[2] Y. H. Liu and Y. Q. Li, A mechanism to pin skyrmions in chiral magnets, J. Phys.: Condens. Matter 25 (2013) 076005;

[3] H. Liu, Y. Q. Li, and J. H. Han, Skyrmion dynamics in multiferroic insulators, Phys. Rev. B 87 (2013) 100402 (R);

[4] S. Zhu and Y. Q. Li, Spin-orbital driven ferroelectricity, J. Phys.: Condens. Matter 26 (2014) 395901;

[5] S. Zhu，Y. Q. Li, and C. D. Batista, Spin-orbit coupling and electronic charge effects in Mott insulators, Phys. Rev. B 90 (19), (2014) 195107;

[6] Y. Akagi, et al., Isolated skyrmions in the CP monlinear sigma model with DM type interaction, Phys. Rev. D 103 (2021) 065008;

[7] H. B. Chen, Y. H. Liu and Y. Q. Li, Electric field control of multiferroic domain wall motion, J. Appl. Phys. 115 (2014) 133913;

[8] H. B. Chen and Y. Q. Li, Electric-field control of elective spin excitations in Neel-type skyrmions, Appl. Phys. Express 12 (2019) 093003;

[9] Y. H. Liu and Y. Q. Li, Dynamics of magnetic skyrmions, Chin. Phys. B 24 (2015) 017506;

[10] R. Wiesendanger, Nanoscale magnetic skyrmions in metallic films and multilayers: a new twist for spintronics, Nature Review Materials, 1 (2016) 1;

[11] C. Reichhardt and C. J. O. Reichhardt, Statics and dynamics of skyrmions interacting withpining: a review, arXiv:2102.10464v1.(2021).

个人简介：

李有泉，教授、博导，1963年出生。于兰州大学物理系先后获学士学位(1983)、硕士学位(1986)、博士学位(1989)。1990年12月至1992年12月于浙江大学从事博士后科研工作。1993年起在浙江大学任教，期间学术访问意大利国际理论物理中心ICTP（1992.7-8；1996.6-9）、瑞士联邦理工EPFL(1997.3-12)、美国辛辛那提大学（1997.12-1998.3）、德国奥格斯堡大学（1999.3-2001.8）、香港中文大学（2002.2-5）、香港大学（2005.5-6；2006.5-6）等。

简介：长期从事理论凝聚态物理研究工作，发表论文160余篇；主持省部级以上科研项目14项，含国家自然科学面上项目8项、国家杰出青年科学基金项目1项、国家重点研发计划项目1项；获国家自然科学二等奖1项、中国高校自然科学一等奖1项；入选“教育部长江学者”（2001年），“新世纪百千万人才工程”国家级人选（2006年），“国家万人计划”--百千万工程领军人才（2014年）；获全国“五一”劳动奖章（2003年）、留学回国人员成就奖章（2003年）及第八届中国青年科技奖（2004年）；曾担任《科学通报》、《Frontiers of Physics in China》、《物理学进展》等期刊编委，现担任中国物理学会秋季会议（CPS Fall Meeting）、全国磁学理论会议等组委会委员。

研究方向：理论凝聚态物理，量子物理新奇效应及其潜在应用