Presentation Information
[PC2-01-INV]Unified description of photoemission and quasiparticle-interference spectra for cuprate superconductors through a fractionalized-electron model
*Shiro Sakai1 (1. Faculty of Science and Technology, Sophia University (Japan))
Keywords:
Cuprate superconductors,ARPES,STM,Quasiparticle interference
In the past few decades, various experimental studies have unveiled anomalous features of cuprate superconductors, while the mechanism of high-temperature superconductivity remains unresolved, partly because experimental data from different experimental tools are independently analyzed, often based on different models. Here, we perform integrated analyses of angle-resolved photoemission spectra (ARPES) and quasiparticle interference (QPI) effects in a unified theoretical framework, from which we reveal the electronic structure of the cuprate in a full energy-momentum space [1].
Our theory is based on a simple two-component fermion model (TCFM), where an electron is fractionalized into a quasiparticle and a hidden fermion representing an incoherent part and the two degrees of freedom hybridize each other. The model has been justified through many-body numerical simulations [2]. Here, we determine the model parameters of the TCFM by fitting the ARPES data for an optimally-doped Bi2Sr2CaCu2O8+δ and calculate the QPI spectra, carefully following the expressions of experimentally-measurable quantities, without conventional replacements with theoretically-easier quantities.
As a result, we find that the TCFM reproduces both experimental data in quantitative details, with essential distinctions from the analysis based on a conventional (tight-binding) model without the electron fractionalization: Our model predicts a signal characteristic of the electron fractionalization in a phase-reference map of the QPI, which is indeed verified in the experimental data. This verification strongly supports a novel type of electron fractionalization occurring in the cuprates. Our integrated analysis also solves a puzzle that has lain between ARPES and QPI data. The overall success of the TCFM offers a comprehensive understanding of the electronic structure of the cuprates.
[1] S. Sakai, Y. Yamaji, F. Imoto, T. Tamegai, A. Kaminski, T. Kondo, Y. Kohsaka, T. Hanaguri, and M. Imada, arXiv:2508.01297
[2] S. Sakai, J. Phys. Soc. Jpn. 92, 092001 (2023)
Our theory is based on a simple two-component fermion model (TCFM), where an electron is fractionalized into a quasiparticle and a hidden fermion representing an incoherent part and the two degrees of freedom hybridize each other. The model has been justified through many-body numerical simulations [2]. Here, we determine the model parameters of the TCFM by fitting the ARPES data for an optimally-doped Bi2Sr2CaCu2O8+δ and calculate the QPI spectra, carefully following the expressions of experimentally-measurable quantities, without conventional replacements with theoretically-easier quantities.
As a result, we find that the TCFM reproduces both experimental data in quantitative details, with essential distinctions from the analysis based on a conventional (tight-binding) model without the electron fractionalization: Our model predicts a signal characteristic of the electron fractionalization in a phase-reference map of the QPI, which is indeed verified in the experimental data. This verification strongly supports a novel type of electron fractionalization occurring in the cuprates. Our integrated analysis also solves a puzzle that has lain between ARPES and QPI data. The overall success of the TCFM offers a comprehensive understanding of the electronic structure of the cuprates.
[1] S. Sakai, Y. Yamaji, F. Imoto, T. Tamegai, A. Kaminski, T. Kondo, Y. Kohsaka, T. Hanaguri, and M. Imada, arXiv:2508.01297
[2] S. Sakai, J. Phys. Soc. Jpn. 92, 092001 (2023)