Details

Autor(en) / Beteiligte

• Chen, Z. Y.
• Zhang, Zheng
• Yang, Shengyuan A.
• Zhao, Y. X.

Titel

Classification of time-reversal-invariant crystals with gauge structures

Ist Teil von

• Nature communications, 2023-02, Vol.14 (1), p.743-743, Article 743

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2023

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• A peculiar feature of quantum states is that they may embody so-called projective representations of symmetries rather than ordinary representations. Projective representations of space groups-the defining symmetry of crystals-remain largely unexplored. Despite recent advances in artificial crystals, whose intrinsic gauge structures necessarily require a projective description, a unified theory is yet to be established. Here, we establish such a unified theory by exhaustively classifying and representing all 458 projective symmetry algebras of time-reversal-invariant crystals from 17 wallpaper groups in two dimensions-189 of which are algebraically non-equivalent. We discover three physical signatures resulting from projective symmetry algebras, including the shift of high-symmetry momenta, an enforced nontrivial Zak phase, and a spinless eight-fold nodal point. Our work offers a theoretical foundation for the field of artificial crystals and opens the door to a wealth of topological states and phenomena beyond the existing paradigms. Projective representations of crystal symmetries are indispensable for understanding artificial crystals. Here, authors establish a unified theory of projective crystal symmetries with time-reversal invariance, and construct models for all 458 projective symmetry algebras for the 17 two-dimensional wallpaper groups.