汇报标题 (Title)：New Materials Exploration in Quantum Spin Liquid and Topological Semimetals（量子自旋液体和拓扑半金属的新资料索求）
汇报人 (Speaker)：冯子力（日本东京大学）
汇报功夫 (Time)：2023年7月3日(周一) 14:00
汇报地址 (Place)：校本部 E106
约请人 (Inviter)：任伟 教授
主办部门：理学院物理系
提要 (Abstract)：
New material exploration is essential for searching for exotic phenomena and extending our understanding of fundamental physics. In this talk, I will mainly talk about our new materials exploration in quantum spin liquid (QSL) and topological semimetals (TSM).
In the first part, by introducing the NMR-friendly element fluorine, we synthesized a new QSL candidate Cu3Zn(OH)6FBr and observed the spin-1/2 spinon excitation providing firm evidence for spin fractionalization in a topologically ordered spin system. Then we built a phase diagram between magnetic ordered Cu4(OH)6FBr and topological order Cu3Zn(OH)6FBr[1-2]. In the second part, since the type of high-energy fermion is limited by Poincare symmetry, new types of fermions without any high-energy counterpart may exist in solid-sate materials. Collaborating with the ARPES group, we observed three fermions in MoP grown by the flux method for the first time, and multiple fermions coexisting in PdBiSe [3-4]. Finally, as a typical transport character in topological magnets, the large anomalous Nernst effect (ANE) was studied. We obtained a recorded ANE signal in polycrystalline topological ferromagnet Fe3Ga alloy by tuning the position of the nodal web. This compound provides a promising candidate for waste heat harvest using ANE [5].
Reference:
[1] Z.L. Feng, W. Yi, et. al. Chin. Phys. Lett. 36, 017502, (2018).
[2] Z.L. Feng, Y. Wei, et. al., Phys. Rev. B 98, 155127, (2018).
[3] B.Q. Lv, Z.L. Feng, Q.N. Xu, et. al. Nature 546, 627-631, (2017).
[4] B.Q. Lv, Z.F. Feng, J.Z. Zhao, et. al., Phys. Rev. B 99, 241104(R) (2019).
[5] Z.L. Feng, S. Minami, et. al., Adv. Funct. Mater. 2206519. (2022)
新资料索求对于寻找奇怪景象和扩大我们对基础物理学的理解至关沉要。本次汇报将重要介绍我们在量子自旋液体（QSL）和拓扑半金属（TSM）方面的新资料索求。在第一部门，我们通过引入核磁共振敦睦的氟元素，合成了新的QSL候选资料Cu3Zn(OH)6FBr，观察到自旋1/2自旋子引发，为拓扑序自旋系统中的自旋分数化引发提供了靠得住证据。而后我们成立了磁性有序Cu4(OH)6FBr和拓扑有序Cu3Zn(OH)6FBr之间的相图。在第二部门，由于高能费米子的类型受限于Poincare对称性，在固态资猜中可能存在没有任何高能对应物的新类型费米子。通过与ARPES课题组合作，我们初次在用通量法成长的MoP中观察到三沉简并费米子，在PdBiSe中观察到多中新型费米子共存。最后，作为拓扑磁体中的一个典型的输运特点，我们钻研了拓扑磁体中的畸形Nernst效应。我们通过调整Nodal web的地位，在多晶拓扑铁磁体Fe3Ga合金中获得了纪录的ANE信号。这为利用ANE进行废热网络提供了一个有但愿的候选资料。
