Spin-Orbital Density Wave and a Mott Insulator in a Two-Orbital Hubbard Model on a Honeycomb Lattice
Name
PhysRevLett.123.087602.pdf
Size
1.87 MB
Format
Adobe PDF
Checksum (MD5)
93bc75bfe97c8b740e82b5d74b19c5dc
Author(s)
Zhu, Zheng
Sheng, D. N.
Fu, Liang
Date Issued
August 2019
Journal
Physical Review Letters
Publisher
American Physical Society (APS)
Citation
Physical Review Letters 123, 8 (August 2019): 087602 © 2019 American Physical Society
Version
Final published version
Abstract
Inspired by the recent discovery of correlated insulating states in twisted bilayer graphene, we study a two-orbital Hubbard model on the honeycomb lattice with two electrons per unit cell. Based on the real-space density matrix renormalization group simulation, we identify a metal-insulator transition around U_{c}/t=2.5–3. In the vicinity of U_{c}, we find strong spin-orbital density wave fluctuations at commensurate wave vectors, accompanied by weaker incommensurate charge density wave fluctuations. The spin-orbital density wave fluctuations are enhanced with increasing system sizes, suggesting the possible emergence of long-range order in the two-dimensional limit. At larger U, our calculations indicate a possible nonmagnetic Mott insulator phase without spin or orbital polarization. Our findings offer new insight into correlated electron phenomena in twisted bilayer graphene and other multiorbital honeycomb materials.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1103/physrevlett.123.087602
