第169回 フロンティア材料研究所学術講演会(Prof. Aftab Alam)
開催日時 | 2023年12月07日 13:00 –15:00 |
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開催場所 | 東京工業大学すずかけ台キャンパス R3棟(地図⑱)1F大会議室/Zoomミーティング |
主催 | 東京工業大学 科学技術創成研究院 フロンティア材料研究所 |
連絡先 | Hena DAS 特任准教授(Email: das.h.aa@m.titech.ac.jp) 東・山本研究室(内線:5315) |
備考 | オンライン参加を希望される方は、こちらからお申し込みください。 |
プログラム等
講師: Prof. Aftab Alam (Department of Physics, Indian Institute of Technology Bombay)
演題: GdAlSi: A potential candidate for altermagnetic topological Weyl semimetal
Abstract:
Spintronics has emerged as a viable alternative to conventional electronics in the past few decades. On one hand, discovery of topological phases of matter with protected spin-polarized states have shown promising applications while on the other hand, new magnetic materials have shown in- triguing phases of collinear antiferromagnets with unconventional spin-splitters. In this work, we report the co-existence of these two interesting phases in a single material: GdAlSi. GdAlSi crys- tallizes in a body-centered tetragonal structure with a non-centrosymmetric space group I41md (109). The magnetization data indicates antiferromagnetic (AFM) ordering with an ordering temperature (TN) 32 K. Ab-initio calculations show GdAlSi to be a collinear antiferromagnetic Weyl semimetal (WSM) with an unconventional momentum-dependent spin splitting (also nomenclature as altermagnetism). Fermi arcs, a characteristic feature of WSMs, have been subsequently observed in angle-resolved photoemission spectroscopy (ARPES) measurements performed on GdAlSi single crystals. Electric and magnetic multipole analysis gives a deeper insight into the symmetry mediated momentumdependent spin splitting which has a strictly non-relativistic origin. To the best of our knowledge, such coexistence of unconventional AFM order and non-trivial topology is unprecedented and has never been observed before in any material which makes GdAlSi a wonder material. Finally, we propose a device which can leverage this unique coexistence leading to practical and efficient topotronic application