Universität zu Köln

Tokuda, Satoru ORCID: 0000-0003-4626-9868, Souma, Seigo, Segawa, Kouji, Takahashi, Takashi, Ando, Yoichi ORCID: 0000-0002-3553-3355, Nakanishi, Takeshi and Sato, Takafumi ORCID: 0000-0002-4544-5463 (2021). Unveiling quasiparticle dynamics of topological insulators through Bayesian modelling. Commun. Phys., 4 (1). BERLIN: NATURE RESEARCH. ISSN 2399-3650

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Abstract

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.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Tokuda, Satoru UNSPECIFIED orcid.org/0000-0003-4626-9868 UNSPECIFIED Souma, Seigo UNSPECIFIED UNSPECIFIED UNSPECIFIED Segawa, Kouji UNSPECIFIED UNSPECIFIED UNSPECIFIED Takahashi, Takashi UNSPECIFIED UNSPECIFIED UNSPECIFIED Ando, Yoichi UNSPECIFIED orcid.org/0000-0002-3553-3355 UNSPECIFIED Nakanishi, Takeshi UNSPECIFIED UNSPECIFIED UNSPECIFIED Sato, Takafumi UNSPECIFIED orcid.org/0000-0002-4544-5463 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-589412
DOI:	10.1038/s42005-021-00673-6
Journal or Publication Title:	Commun. Phys.
Volume:	4
Number:	1
Date:	2021
Publisher:	NATURE RESEARCH
Place of Publication:	BERLIN
ISSN:	2399-3650
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ANGLE-RESOLVED PHOTOEMISSION; PHASE-TRANSITION; NORMALIZING CONSTANTS; BI2SE3; ENERGY Multiple languages Physics, Multidisciplinary Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/58941