Flat bands and ferrimagnetic order in electronically correlated dice-lattice ribbons

Rahul Soni, Nitin Kaushal, Satoshi Okamoto, Elbio Dagotto

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

We study ribbons of the dice two-dimensional lattice (that we call "dice ladders") known to have nontrivial topological properties, such as Chern numbers 2 [Wang and Ran, Phys. Rev. B 84, 241103(R) (2011)PRBMDO1098-012110.1103/PhysRevB.84.241103]. Our main results are two fold. (1) Analyzing the tight-binding model in the presence of Rashba spin-orbit coupling and an external magnetic field, we observed that dice ladders qualitatively display properties similar to their two-dimensional counterpart all the way to the limit of only two legs in the short direction. This includes flat bands near the Fermi level, edge currents and edge charge localization near zero energy when open boundary conditions are used, two chiral edge modes, and a nonzero Hall conductance. (2) We studied the effect of Hubbard correlation U in the two-leg dice ladder using Lanczos and density matrix renormalization group techniques. We show that by increasing U the flat bands split without the need of introducing external fields. Moreover, robust ferrimagnetic order develops. Overall, our work establishes dice ladders as a promising playground to study the combined effect of topology and correlation effects, one of the frontiers in quantum materials.

Original languageEnglish
Article number045105
JournalPhysical Review B
Volume102
Issue number4
DOIs
StatePublished - Jul 15 2020

Funding

We thank Dr. G. Alvarez for the use of the dmrg code. All authors were supported by the US Department of Energy (DOE), Office of Science Basic Energy Sciences (BES), Materials Sciences and Engineering Division.

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