| CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES |
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Itinerant Topological Magnons in SU(2) Symmetric Topological Hubbard Models with Nearly Flat Electronic Bands |
| Zhao-Long Gu1 and Jian-Xin Li1,2* |
1National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, China
2Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China
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| Cite this article: |
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Zhao-Long Gu and Jian-Xin Li 2021 Chin. Phys. Lett. 38 057501 |
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Abstract We show that a suitable combination of flat-band ferromagnetism, geometry and nontrivial electronic band topology can give rise to itinerant topological magnons. An $SU(2)$ symmetric topological Hubbard model with nearly flat electronic bands, on a Kagome lattice, is considered as the prototype. This model exhibits ferromagnetic order when the lowest electronic band is half-filled. Using the numerical exact diagonalization method with a projection onto this nearly flat band, we can obtain the magnonic spectra. In the flat-band limit, the spectra exhibit distinct dispersions with Dirac points, similar to those of free electrons with isotropic hoppings, or a local spin magnet with pure ferromagnetic Heisenberg exchanges on the same geometry. Significantly, the non-flatness of the electronic band may induce a topological gap at the Dirac points, leading to a magnonic band with a nonzero Chern number. More intriguingly, this magnonic Chern number changes its sign when the topological index of the electronic band is reversed, suggesting that the nontrivial topology of the magnonic band is related to its underlying electronic band. Our work suggests interesting directions for the further exploration of, and searches for, itinerant topological magnons.
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Received: 07 February 2021
Published: 02 May 2021
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| PACS: |
75.10.Lp
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(Band and itinerant models)
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03.75.Lm
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(Tunneling, Josephson effect, Bose-Einstein condensates in periodic potentials, solitons, vortices, and topological excitations)
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71.27.+a
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(Strongly correlated electron systems; heavy fermions)
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| Fund: Supported by the National Natural Science Foundation of China (Grant No. 11774152), and National Key R&D Program of China (Grant No. 2016YFA0300401). |
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| [1] | Bansil A, Lin H, and Das T 2016 Rev. Mod. Phys. 88 021004 |
| [2] | Hasan M Z and Kane C L 2010 Rev. Mod. Phys. 82 3045 |
| [3] | Qi X L and Zhang S C 2011 Rev. Mod. Phys. 83 1057 |
| [4] | Haldane F D M 1988 Phys. Rev. Lett. 61 2015 |
| [5] | Kitaev A Y 2001 Phys. Usp. 44 131 |
| [6] | Kane C L and Mele E J 2005 Phys. Rev. Lett. 95 226801 |
| [7] | Bernevig B A, Hughes T L, and Zhang S C 2006 Science 314 1757 |
| [8] | Qi X L, Hughes T L, Raghu S, and Zhang S C 2009 Phys. Rev. Lett. 102 187001 |
| [9] | Yu S L, Xie X C, and Li J X 2011 Phys. Rev. Lett. 107 010401 |
| [10] | Berry M V 1984 Proc. R. Soc. A 392 45 |
| [11] | Thouless D J, Kohmoto M, Nightingale M P, and den Nijs M 1982 Phys. Rev. Lett. 49 405 |
| [12] | Simon B 1983 Phys. Rev. Lett. 51 2167 |
| [13] | Wan X, Turner A M, Vishwanath A, and Savrasov S Y 2011 Phys. Rev. B 83 205101 |
| [14] | Onose Y, Ideue T, Katsura H, Shiomi Y, and Nagaosa N 2010 Science 329 297 |
| [15] | Zhang L, Ren J, Wang J S, and Li B 2013 Phys. Rev. B 87 144101 |
| [16] | Chisnell R, Helton J, Freedman D, Singh D, and Bewley R 2015 Phys. Rev. Lett. 115 147201 |
| [17] | Li F Y, Li Y D, Kim Y B, Balents L, and Yu Y 2016 Nat. Commun. 7 12691 |
| [18] | Mook A, Henk J, and Mertig I 2016 Phys. Rev. Lett. 117 157204 |
| [19] | Owerre S A 2016 J. Phys.: Condens. Matter 28 386001 |
| [20] | Roldán-Molina A, Nunez A S, and Fernández-Rossier J 2016 New J. Phys. 18 045015 |
| [21] | Malki M and Schmidt K P 2017 Phys. Rev. B 95 195137 |
| [22] | Su Y, Wang X S, and Wang X R 2017 Phys. Rev. B 95 224403 |
| [23] | Laurell P and Fiete G A 2017 Phys. Rev. Lett. 118 177201 |
| [24] | McClarty P A, Krger F, Guidi T, Parker S F, and Refson K 2017 Nat. Phys. 13 736 |
| [25] | Mook A, Henk J, and Mertig I 2017 Phys. Rev. B 95 014418 |
| [26] | Li K, Li C, Hu J, Li Y, and Fang C 2017 Phys. Rev. Lett. 119 247202 |
| [27] | Yao W, Li C, Wang L, Xue S, and Dan Y 2018 Nat. Phys. 14 1011 |
| [28] | Bao S, Wang J, Wang W, Cai Z, and Li S 2018 Nat. Commun. 9 2591 |
| [29] | Chen L, Chung J H, Gao B, Chen T, and Stone M B 2018 Phys. Rev. X 8 041028 |
| [30] | Pershoguba S S, Banerjee S, Lashley J et al. 2018 Phys. Rev. X 8 011010 |
| [31] | Su X F, Gu Z L, Dong Z Y, and Li J X 2018 Phys. Rev. B 97 245111 |
| [32] | Gu Z L, Dong Z Y, Yu S L, and Li J X 2019 arXiv:1908.09255 [cond-mat.str-el] |
| [33] | Chumak A V, Vasyuchka V I, Serga A A, and Hillebrands B 2015 Nat. Phys. 11 453 |
| [34] | Dzyaloshinsky I 1958 J. Phys. Chem. Solids 4 241 |
| [35] | Moriya T 1960 Phys. Rev. 120 91 |
| [36] | Holstein T and Primakoff H 1940 Phys. Rev. 58 1098 |
| [37] | Tang E, Mei J W, and Wen X G 2011 Phys. Rev. Lett. 106 236802 |
| [38] | Wang F and Ran Y 2011 Phys. Rev. B 84 241103 |
| [39] | Sun K, Gu Z, Katsura H, and Sarma S D 2011 Phys. Rev. Lett. 106 236803 |
| [40] | Wang Y F, Gu Z C, Gong C D, and Sheng D N 2011 Phys. Rev. Lett. 107 146803 |
| [41] | Neupert T, Santos L, Chamon C, and Mudry C 2011 Phys. Rev. Lett. 106 236804 |
| [42] | Sheng D N, Gu Z C, Sun K, and Sheng L 2011 Nat. Commun. 2 389 |
| [43] | Regnault N and Bernevig B A 2011 Phys. Rev. X 1 021014 |
| [44] | Tasaki H 1992 Phys. Rev. Lett. 69 1608 |
| [45] | Mielke A 1993 Phys. Lett. A 174 443 |
| [46] | Mielke A and Tasaki H 1993 Commun. Math. Phys. 158 341 |
| [47] | Doretto R L and Goerbig M O 2015 Phys. Rev. B 92 245124 |
| [48] | Su X F, Gu Z L, Dong Z Y, Yu S L, and Li J X 2019 Phys. Rev. B 99 014407 |
| [49] | Neupert T, Santos L, Ryu S, Chamon C, and Mudry C 2012 Phys. Rev. Lett. 108 046806 |
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