Home >  研究会等 > Generation scheme of symmetry-adapted closest Wannier model

Generation scheme of symmetry-adapted closest Wannier model

日程 : 2024年6月21日(金) 4:00 pm - 5:00 pm 場所 : 物性研究所6階第5セミナー室(A615)及び ZOOM(Hybrid) 講師 : Rikuto Oiwa 所属 : RIKEN CEMS 世話人 : Takahiro Misawa (63492)
e-mail: tmisawa@issp.u-tokyo.ac.jp
講演言語 : 英語

T.Ozaki has recently developed a new method to construct the closest Wannier (CW) orbitals to a given set of localized guiding orbitals [1]. In the CW formalism, the disentanglement of bands is achieved with no iterative calculations, significantly reducing computational costs. In this talk, I will present a generation scheme of the CW model that respects the symmetry of the system by introducing the post-processing symmetrization step based on the symmetry-adapted multipole basis (SAMB) [2]. Since the symmetry properties of the CW orbital and its guiding atomic orbital are equivalent, we can define SAMBs as the complete and orthonormal matrix basis set in the Hilbert space of the CW orbitals. It is shown that the CW Hamiltonian can be expressed as a linear combination of SAMBs belonging to the identity irreducible representation, and the symmetry of the model is fully recovered. We demonstrate how our method works in the case of Nb. We further show an additional usefulness of the present method by modeling the chiral Tellurium crystal. We show that the weight of the electric toroidal quadrupole (Gu) is most dominant and much larger than that of the electric toroidal monopole (G0), and Gu plays an important role in stabilizing the helical structure of Tellurium. The present method is implemented in the open-source Python library, SymClosestWannier [3].

[1] T. Ozaki, arXiv:2306.15296, (2023).

[2] H. Kusunose, RO, and S. Hayami, Phys. Rev. B 107, 195118 (2023).

[3] RO, A. Inda, S. Hayami, T. Nomoto, R. Arita, and H. Kusunose, https://github.com/CMT-MU/SymClosestWannier

(公開日: 2024年06月05日)