Superfluid density and collective modes of fermion superfluid in dice lattice

doi:10.1038/s41598-021-93007-z

	Superfluid density and collective modes of fermion superfluid in dice lattice
	Wu, Yu-Rong 1; Zhang, Xiao-Fei 2,3; Liu, Chao-Fei 4; Liu, Wu-Ming 5,6; Zhang, Yi-Cai 1
刊名	SCIENTIFIC REPORTS
	2021-06-30
卷号	11 期号:1 页码:17
ISSN号	2045-2322
DOI	10.1038/s41598-021-93007-z
英文摘要	The superfluid properties of attractive Hubbard model in dice lattice are investigated. It is found that three superfluid order parameters increase as the interaction increases. When the filling factor falls into the flat band, due to the infinite large density of states, the resultant superfluid order parameters are proportional to interaction strength, which is in striking contrast with the exponentially small counterparts in usual superfluid (or superconductor). When the interaction is weak, and the filling factor is near the bottom of the lowest band (or the top of highest band), the superfluid density is determined by the effective mass of the lowest (or highest) single-particle band. When the interaction is strong and filling factor is small, the superfluid density is inversely proportional to interaction strength, which is related to effective mass of tightly bound pairs. In the strong interaction limit and finite filling, the asymptotic behaviors of superfluid density can be captured by a parabolic function of filling factor. Furthermore, when the filling is in flat band, the superfluid density shows a logarithmic singularity as the interaction approaches zero. In addition, there exist three undamped collective modes for strong interactions. The lowest excitation is gapless phonon, which is characterized by the total density oscillations. The two others are gapped Leggett modes, which correspond relative density fluctuations between sublattices. The collective modes are also reflected in the two-particle spectral functions by sharp peaks. Furthermore, it is found that the two-particle spectral functions satisfy an exact sum-rule, which is directly related to the filling factor (or density of particle). The sum-rule of the spectral functions may be useful to distinguish between the hole-doped and particle-doped superfluid (superconductor) in experiments.
资助项目	NSFC[11874127] ; NSFC[61835013] ; NSFC[11875149] ; NSFC[61565007] ; Guangzhou University ; National Natural Science Foundation of China[11775253] ; Key Research Program of Frontier Sciences, CAS[ZDBS-LY-7016] ; Youth Jing-gang Scholars Program in Jiangxi Province ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; National Key R&D Program of China[2016YFA0301500] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB01020300] ; Strategic Priority Research Program of the Chinese Academy of Sciences[XDB21030300]
WOS关键词	BCS ; SUPERCONDUCTIVITY ; LOCALIZATION
WOS研究方向	Science & Technology - Other Topics
语种	英语
出版者	NATURE RESEARCH
WOS记录号	WOS:000671791200001
资助机构	NSFC ; NSFC ; Guangzhou University ; Guangzhou University ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Key Research Program of Frontier Sciences, CAS ; Key Research Program of Frontier Sciences, CAS ; Youth Jing-gang Scholars Program in Jiangxi Province ; Youth Jing-gang Scholars Program in Jiangxi Province ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; NSFC ; NSFC ; Guangzhou University ; Guangzhou University ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Key Research Program of Frontier Sciences, CAS ; Key Research Program of Frontier Sciences, CAS ; Youth Jing-gang Scholars Program in Jiangxi Province ; Youth Jing-gang Scholars Program in Jiangxi Province ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; NSFC ; NSFC ; Guangzhou University ; Guangzhou University ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Key Research Program of Frontier Sciences, CAS ; Key Research Program of Frontier Sciences, CAS ; Youth Jing-gang Scholars Program in Jiangxi Province ; Youth Jing-gang Scholars Program in Jiangxi Province ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences ; NSFC ; NSFC ; Guangzhou University ; Guangzhou University ; National Natural Science Foundation of China ; National Natural Science Foundation of China ; Key Research Program of Frontier Sciences, CAS ; Key Research Program of Frontier Sciences, CAS ; Youth Jing-gang Scholars Program in Jiangxi Province ; Youth Jing-gang Scholars Program in Jiangxi Province ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; Program of Qing-jiang Excellent Yong Talents, Jiangxi University of Science and Technology ; National Key R&D Program of China ; National Key R&D Program of China ; Strategic Priority Research Program of the Chinese Academy of Sciences ; Strategic Priority Research Program of the Chinese Academy of Sciences
内容类型	期刊论文
源URL	[http://210.72.145.45/handle/361003/10666]
专题	中国科学院国家授时中心
通讯作者	Zhang, Yi-Cai
作者单位	1.Guangzhou Univ, Sch Phys & Mat Sci, Guangzhou 510006, Peoples R China 2.Chinese Acad Sci, Natl Time Serv Ctr, Key Lab Time & Frequency Primary Stand, Xian 710600, Peoples R China 3.Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China 4.Jiangxi Univ Sci & Technol, Sch Sci, Ganzhou 341000, Peoples R China 5.Chinese Acad Sci, Inst Phys, Beijing Natl Lab Condensed Matter Phys, Beijing 100190, Peoples R China 6.Songshan Lake Mat Lab, Dongguan 523808, Guangdong, Peoples R China
推荐引用方式 GB/T 7714	Wu, Yu-Rong,Zhang, Xiao-Fei,Liu, Chao-Fei,et al. Superfluid density and collective modes of fermion superfluid in dice lattice[J]. SCIENTIFIC REPORTS,2021,11(1):17.
APA	Wu, Yu-Rong,Zhang, Xiao-Fei,Liu, Chao-Fei,Liu, Wu-Ming,&Zhang, Yi-Cai.(2021).Superfluid density and collective modes of fermion superfluid in dice lattice.SCIENTIFIC REPORTS,11(1),17.
MLA	Wu, Yu-Rong,et al."Superfluid density and collective modes of fermion superfluid in dice lattice".SCIENTIFIC REPORTS 11.1(2021):17.