题目：Semi-Dirac fermions in hexagonal closed-packed cadmium
报告人：Alaska Subedi教授，法国巴黎综合理工学院
时间：2025年11月26日（周三）上午10:00
地点：国家脉冲强磁场科学中心C204
报告摘要：
Semi-Dirac fermions are massless in one direction and massive in the perpendicular directions. Such quasiparticles have been proposed in various contexts in condensed matter. In this talk, I'll discuss the results of our first principles calculations that show a pair of semi-Dirac bands anti-crossing at -3 eV below the Fermi level in the electronic structure of hexagonal close-packed cadmium. The linear out-of-plane dispersion persists up to the Fermi level. We demonstrate that the direction-dependent linear and quadratic dispersions occur due to orientation-sensitive hybridization between the s and pz orbitals. The upper semi-Dirac band produces a lense-shaped nonellipsoidal Fermi sheet whose cross-section area has a momentum dependence that is in excellent agreement with the experimentally measured period of Sondheimer oscillations.
报告人简介：
Alaska Subedi is a Permanent Researcher (Chargé de Recherche) of the French National Center for Scientific Research (CNRS) at the Centre de Physique Théorique, École Polytechnique, France, a position he has held since 2017. He earned his PhD in Physics from the University of Tennessee, Knoxville, USA (2006–2010), conducting his research at Oak Ridge National Laboratory. His postdoctoral career includes positions at the Max Planck Institute for Solid State Research in Stuttgart with Lilia Boeri (2010-2012) and at the Centre de Physique Théorique, École Polytechnique with Antoine Georges (2012-2014). He subsequently served as an Independent Research Group Leader at the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg (2014-2015), before returning to the Centre de Physique Théorique as a Research Associate (2016-2017). His research focuses on theoretical condensed matter physics, including nonlinear phononics, light-induced control of materials, superconductivity, charge density waves, and thermoelectric properties. He has authored over 60 refereed publications in prestigious journals such as Nature, Science Advances, and the Physical Review series.
