六方TTe（T=Hf、Zr、Ti）晶体中的多种拓扑电子与声子准粒子激发
Multiple topological electronic and phononic quasiparticle excitations in hexagonal TTe (T=Hf, Zr & Ti) crystals
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中文总结 AI 辅助
本研究通过从头算计算，提出HfTe类材料，其电子与声子谱中同时存在多种拓扑准粒子激发，且该类材料的拓扑相具有实验可观测性。
中文摘要 AI 辅助
拓扑费米子与玻色子的研究开启了凝聚态物理学的新篇章，揭示出丰富且非常规的现象。在量子场论中，狄拉克费米子、外尔费米子等奇异准粒子激发可作为直接类比，其近期的实验实现引发了学界对这些拓扑准粒子的浓厚兴趣。尽管已有诸多关于非常规费米子准粒子共存的报道，如自旋-1/2（I型、II型、III型）、自旋-1（三重简并）、节点线（I型、II型、III型）等，但单一材料中同时在电子谱和声子谱中存在此类准粒子的报道仍极为有限。本研究采用最先进的从头算计算，提出HfTe类材料，其同时存在I型、II型、III型外尔相和节点线相，且电子态与声子态中均存在赝自旋-1/自旋-1准粒子；研究发现，这些激发对交换关联泛函、自旋轨道耦合及晶格参数的变化具有鲁棒性，证实该类材料中的多种拓扑相有望在实验中观测到。
英文摘要
The exploration of topological fermions and bosons marks a new chapter in condensed matter physics, unveiling rich and unconventional phenomena. Particularly in quantum field theory, exotic quasiparticle excitations such as Dirac and Weyl fermions can serve as direct analogs, and their recent experimental realizations have sparked significant interest in these topological quasiparticles. Although there are various reports on the coexistence of unconventional fermionic quasiparticles such as spin-1/2 (type-I, type-II, & type-III), spin-1 (threefold degeneracy), nodal line (type-I, type-II, & type-III) and others, reports on the simultaneous presence of such quasiparticles in both electronic and phononic spectra within a single material remain extremely limited. Herein, using state-of-theart ab initio calculations, we propose the HfTe class of materials, which hosts coexisting type-I, type-II, and type-III Weyl and nodal line phases, along with pseudospin-1/spin-1 quasiparticles in both electronic and phononic states. We have found that these excitations are robust against variations in exchange-correlation functionals, spin-orbit coupling, and lattice parameters, confirming that multiple topological phases in this class of materials are likely to be observed experimentally.
