题目：Double-Weyl Phonons in Transition-Metal Monosilicides

报告人：张田田 在读博士

                中国科学院物理研究所

时间：2018年1月15日上午9:30

地点：国家脉冲强磁场科学中心C204

报告摘要：

We employed ab initio calculations to identify a class of crystalline materials of MSi(M=Fe, Co, Mn, Re, Ru) having double-Weyl points in both their acoustic and optical phonon spectra. They exhibit novel topological points termed “spin-1 Weyl point” at the Brillouin zone center and “charge-2 Dirac point” at the zone corner. The corresponding gapless surface phonon dispersions are two helicoidal sheets whose isofrequency contours form a single noncontractible loop in the surface Brillouin zone. In addition, the global structure of the surface bands can be analytically expressed as double-periodic Weierstrass elliptic functions.

参考文献：

[1].Tiantian Zhang, Zhida Song, A. Alexandradinata, Hongming Weng, Chen Fang, Ling Lu, Zhong Fang. Double-Weyl phonons in transition-metal monosilicides.Phys. Rev. Lett. 120, 016401(2017).

[2]. B. Bradlyn, J. Cano, Z. Wang, M. G. Vergniory, C. Felser, R. J. Cava, and B. A. Bernevig, Beyond dirac and Weyl fermions: Unconventional quasiparticles in conventional crystals, Science 353, aaf5037 (2016).

[3]. R. M. Geilhufe, S. S. Borysov, A. Bouhon, and A. V. Balatsky, Data mining for three-dimensional organic dirac materials: Focus on space group 19, Sci. Rep. 7, 7298 (2017).

[4]. C. Fang, L. Lu, J. Liu, and L. Fu, Topological semimetals with helicoid surface states, Nat. Phys. 12, 936 (2016).

报告人简介：

张田田，2014年毕业于北京师范大学物理系，现为中科院物理所研究生，直博四年级。2016年至今，先后在PRL、PRB刊物发表论文4篇。

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