У оквиру семинара Центра за чврсто стање и нове материјале Института за физику у Београду, у уторак, 13. августа 2024. године у 13 часова у читаоници библиотеке „др Драган Поповић“, проф. Шианг Јуан (East China Normal University, Шангај, Кина) одржаће предавање:
Topology physics in new dimensions
САЖЕТАК:
Generally, physical law varies with the dimensions of systems. In solid-state physics, quantized magnetic fields can effectively drive the electronic states into new dimensions, revealing the unique quantum
phenomena. In this report, we will introduce our advances in topology physics within new dimensions including the discovery of 1D Weyl fermion, 3D Van Hov Singularity and 3D quantum Hall effect. The quantum Hall effect (QHE), discovered decades ago, remains one of the most vital phenomena in condensed matter physics. We extend the QHE from two dimension to three dimension and discover the bulk contribution from Weyl orbits by fabricating the wedge-shaped Cd3As2 nanostructures and conducting magneto-transport measurements[1]. To detect electronic states in a larger energy range under magnetic fields, we develop the optical pipe probe coupled with a closed-cycle superconducting magnet and the FTIR spectrometer, allowing experimental energy range from several meV to eV. Utilizing ultra-high magnetic fields (up to 35 T), the topological insulator HfTe5 is driven into the extreme quantum limit. With the one-dimensional Weyl mode realized, we detect the divergent optical conductivity of one dimensional massless Weyl fermions[2]. Additionally, we control the exchange effect in topological magnet EuCd2As2 by external magnetic fields and realize a rare case of three-dimensional van Hove singularity evidenced by magneto-infrared spectroscopy[3].
References:
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2. W. Wu, Z. Shi, Y. Du, Y. Wang, F. Qin, X. Meng, B. Liu, Y. Ma, Z. Yan, M. Ozerov, C. Zhang*, H.-Z. Lu, J. Chu & X. Yuan*. Topological Lifshitz transition and one-dimensional Weyl mode in HfTe5. Nat. Mater. 22, 84–91 (2023).
3. W. Wu, Z. Shi, M. Ozerov, Y. Du, Y. Wang, X.-S. Ni, X. Meng, X. Jiang, G. Wang, C. Hao, X. Wang, P. Zhang, C. Pan, H. Pan, Z. Sun, R. Yang, Y. Xu, Y. Hou, Z. Yan, C. Zhang, H.-Z. Lu, J. Chu & X. Yuan*. The discovery of three-dimensional Van Hove singularity. Nat Commun 15, 2313 (2024).