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セガワ コウジ
SEGAWA KOJI
瀬川 耕司 所属 京都産業大学 理学部 物理科学科 職種 教授 |
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| 言語種別 | 英語 |
| 発行・発表の年月 | 2021/07 |
| 形態種別 | 研究論文 |
| 標題 | Unveiling quasiparticle dynamics of topological insulators through Bayesian modelling |
| 執筆形態 | その他 |
| 掲載誌名 | COMMUNICATIONS PHYSICS |
| 出版社・発行元 | NATURE RESEARCH |
| 巻・号・頁 | 4(1) |
| 著者・共著者 | Satoru Tokuda,Seigo Souma,Kouji Segawa,Takashi Takahashi,Yoichi Ando,Takeshi Nakanishi,Takafumi Sato |
| 概要 | Extracting quasiparticle dispersion from photoemission data is challenging and often results in confusion when investigating low-energy excitations. As a solution the authors demonstrate a technique, which applies Bayesian analysis to extract the quasiparticle dynamics of a topological insulator from angle resolved photoemission spectroscopy (ARPES) data, and could be applied to other quantum materials.Quasiparticle - a key concept to describe interacting particles - characterizes electron-electron interaction in metals (Fermi liquid) and electron pairing in superconductors. While this concept essentially relies on the simplification of hard-to-solve many-body problem into one-particle picture and residual effects, a difficulty in disentangling many-body effects from experimental quasiparticle signature sometimes hinders unveiling intrinsic low-energy dynamics, as highlighted by the fierce controversy on the origin of Dirac-band anomaly in graphene and dispersion kink in high-temperature superconductors. Here, we propose an approach to solve this fundamental problem - the Bayesian modelling of quasiparticles. We have chosen a topological insulator TlBi(S,Se)(2) as a model system to formulate an inverse problem of quasiparticle spectra with semiparametric Bayesian analysis, and successfully extracted one-particle and many-body characteristics, i.e. the intrinsic energy gap and unusual lifetime in Dirac-quasiparticle bands. Our approach is widely applicable to clarify the quasiparticle dynamics of quantum materials. |
| DOI | 10.1038/s42005-021-00673-6 |
| ISSN | 2399-3650 |