Unveiling quasiparticle dynamics of topological insulators through Bayesian modelling
Unveiling quasiparticle dynamics of topological insulators through Bayesian modelling
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DOI：
10.1038/s42005-021-00673-6
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发表时间：
2021-07
影响因子：
5.5
通讯作者：
Satoru Tokuda;S. Souma;K. Segawa;Takashi Takahashi;Y. Ando;T. Nakanishi;Takafumi Sato
中科院分区：
文献类型：
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作者：
Satoru Tokuda;S. Souma;K. Segawa;Takashi Takahashi;Y. Ando;T. Nakanishi;Takafumi Sato
准粒子是描述相互作用粒子的一个关键概念，它表征了金属（费米液体）中的电子-电子相互作用和超导体中的电子配对。虽然这一概念本质上依赖于将难以解决的多体问题简化为单粒子图像和剩余效应，但从实验准粒子签名中分离多体效应的困难有时会阻碍揭示内在的低能动力学，正如对石墨烯中的Dirac带异常和高温超导体中的色散扭结的起源的激烈争议所强调的那样。在这里，我们提出了一种方法来解决这个基本问题-准粒子的贝叶斯建模。我们选择拓扑绝缘体TlBi（S，Se）2作为模型系统，用半参数贝叶斯分析方法建立了准粒子谱的反问题，成功地提取了Dirac准粒子带的单粒子和多体特征，即内禀能隙和反常寿命.我们的方法是广泛适用于澄清量子材料的准粒子动力学。
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)2as 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.