Absence of BCS-BEC crossover in FeSe0.45Te0.55 superconductor

doi:10.1088/1674-1056/ad51f9

Abstract In iron-based superconductor Fe(Se,Te), a flat band-like feature near the Fermi level was observed around the Brillouin zone center in the superconducting state. It is under debate whether this is the evidence on the presence of the BCS-BEC [Bardeen-Cooper-Schrieffer (BCS), Bose-Einstein condensation (BEC)] crossover in the superconductor. High-resolution laser-based angle-resolved photoemission measurements are carried out on high quality single crystals of FeSe$_{0.45}$Te$_{0.55}$ superconductor to address the issue. By employing different polarization geometries, we have resolved and isolated the d$_{yz}$ band and the topological surface band, making it possible to study their superconducting behaviors separately. The d$_{yz}$ band alone does not form a flat band-like feature in the superconducting state and the measured dispersion can be well described by the BCS picture. We find that the flat band-like feature is formed from the combination of the d$_{yz}$ band and the topological surface state band in the superconducting state. These results reveal the origin of the flat band-like feature and rule out the presence of BCS-BEC crossover in Fe(Se,Te) superconductor.

Keywords: FeSe$_{0.45}$Te$_{0.55}$ ARPES electronic structure superconducting gap BCS-BEC crossover

Received: 24 May 2024
Revised: 30 May 2024
Accepted manuscript online: 30 May 2024

PACS:	74.25.Jb	(Electronic structure (photoemission, etc.))
	74.20.Fg	(BCS theory and its development)
	74.20.Mn	(Nonconventional mechanisms)
	71.20.-b	(Electron density of states and band structure of crystalline solids)

Fund: Projects supported by the National Key Research and Development Program of China (Grant Nos. 2021YFA1401800, 2022YFA1604200, 2022YFA1403900, and 2023YFA1406000), the National Natural Science Foundation of China (Grant Nos. 12488201, 12374066, 12074411, and 12374154), the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant Nos. XDB25000000 and XDB33000000), the Innovation Program for Quantum Science and Technology (Grant No. 2021ZD0301800), the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. Y2021006), and the Synergetic Extreme Condition User Facility (SECUF).

Corresponding Authors: Lin Zhao, Xing-Jiang Zhou
E-mail: lzhao@iphy.ac.cn;XJZhou@iphy.ac.cn

Cite this article:

Junjie Jia(贾俊杰), Yadong Gu(谷亚东), Chaohui Yin(殷超辉), Yingjie Shu(束英杰), Yiwen Chen(陈逸雯), Jumin Shi(史聚民), Xing Zhang(张杏), Hao Chen(陈浩), Taimin Miao(苗泰民), Xiaolin Ren(任晓琳), Bo Liang(梁波), Wenpei Zhu(朱文培), Neng Cai(蔡能), Fengfeng Zhang(张丰丰), Shenjin Zhang(张申金), Feng Yang(杨峰), Zhimin Wang(王志敏), Qinjun Peng(彭钦军), Zuyan Xu(许祖彦), Hanqing Mao(毛寒青), Guodong Liu(刘国东), Zhian Ren(任治安), Lin Zhao(赵林), and Xing-Jiang Zhou(周兴江) Absence of BCS-BEC crossover in FeSe_0.45Te_0.55 superconductor 2024 Chin. Phys. B 33 077404

[1] Bardeen J, Cooper L N and Schrieffer J R 1957 Phys. Rev. J. Arch. 108 1175
[2] Dalfovo F and Giorgini S 1999 Rev. Mod. Phys. 71 463
[3] Stringari S, Pitaevskii L P and Giorgini S 2008 Rev. Mod. Phys. 80 1215
[4] Eagles D M 1969 Phys. Rev. Jour. Arch. 186 456
[5] Leggett A J 1980 Proceedings of the XVIth Karpacz Winter School of Theoretical Physics, Karpacz, Poland Springer-Verlag pp. 13-27
[6] Nozieres P and Schmitt-Rink S 1985 J. Low Temp. Phys. 59 195
[7] Chen Q J, Stajic J, Tan S and Levin K 2005 Phys. Rep. 412 1-88
[8] Randeria M and Taylor E 2014 Ann. Rev. Con. Matter Phys. 5 209
[9] Chen Q J, Wang Z Q, Boyack R, Yang S L and Levin K 2024 Rev. Mod. Phys. 96 025002
[10] Lubashevsky Y, Lahoud E, Chashka K, Podolsky D and Kanigel A 2012 Nat. Phys. 8 309
[11] Kasahara S, Watashige T, Hanaguri T, Kohsaka Y, Yamashita T, Shimoyama Y, Mizukami Y, Endo R, Ikeda H, Aoyama K, Terashima T, Uji S, Wolf T, Löhneysen H, Shibauchi T and Matsuda Y 2014 Proc. Natl. Acad. Sci. USA 111 16309
[12] Okazaki K, Ito Y, Ota Y, Kotani Y, Shimojima T, Kiss T, Watanabe S, Chen C T, Niitaka S, Hanaguri T, Takagi H, Chainani A and Shin S 2014 Sci. Rep. 4 4109
[13] Rinott S, Chashka K B, Ribak A, Rienks E D L, Taleb-Ibrahimi A, Fevre P L, Bertran F, Randeria M and Kanigel A 2017 Sci. Adv. 3 e1602372
[14] Hashimoto T, Ota Y, Tsuzuki A, Nagashima T, Fukushima T, Kasahara S, Matsuda Y, Matsuura K, Mizukami Y, Shibauchi S, Shin S and Okazaki K 2020 Sci. Adv. 6 eabb9052
[15] Gu Y D, Zhou M H, Zhang M D, Wu Y W, Ruan B B, Hou X Y, Zhang F, Jiang P J, Yang Q S, Li G, Ma M W, Chen G F, Shan L and Ren Z A 2022 Sci. China Mater. 65 2472
[16] Zhou X J, He S L, Liu G D, Zhao Lin, Yu L and Zhang W T 2018 Rep. Pro. Phys. 81 062101
[17] Zhang P, Yaji K, Hashimoto T, Ota Y, Kondo T, Okazaki K, Wang Z J, Wen J S, Gu G D, Ding H and Shin S 2018 Science 360 182
[18] Zhang P, Wang Z J, Wu X X, Yaji K, Ishida Y, Kohama Y, Dai G Y, Sun Y, Bareille C, Kuroda K, 2019 Nat. Phys. 15 41

[1]	Negligible normal fluid in superconducting state of heavily overdoped Bi₂Sr₂CaCu₂O_8+δ detected by ultra-low temperature angle-resolved photoemission spectroscopy Chaohui Yin(殷超辉), Qinghong Wang(汪清泓), Yuyang Xie(解于洋), Yiwen Chen(陈逸雯), Junhao Liu(刘俊豪), Jiangang Yang(杨鉴刚), Junjie Jia(贾俊杰), Xing Zhang(张杏), Wenkai Lv(吕文凯), Hongtao Yan(闫宏涛), Hongtao Rong(戎洪涛), Shenjin Zhang(张申金), Zhimin Wang(王志敏), Nan Zong(宗楠), Lijuan Liu(刘丽娟), Rukang Li(李如康), Xiaoyang Wang(王晓洋), Fengfeng Zhang(张丰丰), Feng Yang(杨峰), Qinjun Peng(彭钦军), Zuyan Xu(许祖彦), Guodong Liu(刘国东), Hanqing Mao(毛寒青), Lin Zhao(赵林), Xintong Li(李昕彤), and Xingjiang Zhou(周兴江). Chin. Phys. B, 2024, 33(7): 077405.
[2]	Wafer-scale 30° twisted bilayer graphene epitaxially grown on Cu_0.75Ni_0.25 (111) Peng-Cheng Ma(马鹏程), Ao Zhang(张翱), Hong-Run Zhen(甄洪润), Zhi-Cheng Jiang(江志诚), Yi-Chen Yang(杨逸尘), Jian-Yang Ding(丁建阳), Zheng-Tai Liu(刘正太), Ji-Shan Liu(刘吉山), Da-Wei Shen(沈大伟), Qing-Kai Yu(于庆凯), Feng Liu(刘丰), Xue-Fu Zhang(张学富), and Zhong-Hao Liu(刘中灏). Chin. Phys. B, 2024, 33(6): 066101.
[3]	Electronic structure and effective mass of pristine and Cl-doped CsPbBr₃ Zhiyuan Wei(魏志远), Yu-Hao Wei(魏愉昊), Shendong Xu(徐申东), Shuting Peng(彭舒婷), Makoto Hashimoto, Donghui Lu(路东辉), Xu Pan(潘旭), Min-Quan Kuang(匡泯泉), Zhengguo Xiao(肖正国), and Junfeng He(何俊峰). Chin. Phys. B, 2024, 33(5): 057403.
[4]	Geometries and electronic structures of Zr_nCu(n =2-12) clusters: A joint machine-learning potential density functional theory investigation Yizhi Wang(王一志), Xiuhua Cui(崔秀花), Jing Liu(刘静), Qun Jing(井群), Haiming Duan(段海明), and Haibin Cao(曹海宾). Chin. Phys. B, 2024, 33(1): 016109.
[5]	Optical manipulation of the topological phase in ZrTe₅ revealed by time- and angle-resolved photoemission Chaozhi Huang(黄超之), Chengyang Xu(徐骋洋), Fengfeng Zhu(朱锋锋), Shaofeng Duan(段绍峰), Jianzhe Liu(刘见喆), Lingxiao Gu(顾凌霄), Shichong Wang(王石崇), Haoran Liu(刘浩然), Dong Qian(钱冬), Weidong Luo(罗卫东), and Wentao Zhang(张文涛). Chin. Phys. B, 2024, 33(1): 017901.
[6]	Electronic structure study of the charge-density-wave Kondo lattice CeTe₃ Bo Wang(王博), Rui Zhou(周锐), Xuebing Luo(罗学兵), Yun Zhang(张云), and Qiuyun Chen(陈秋云). Chin. Phys. B, 2023, 32(9): 097103.
[7]	Pressure-induced phase transition and electronic structure evolution in layered semimetal HfTe₂ Mei-Guang Zhang(张美光), Lei Chen(陈磊), Long Feng(冯龙), Huan-Huan Tuo(拓换换), Yun Zhang(张云), Qun Wei(魏群), and Pei-Fang Li(李培芳). Chin. Phys. B, 2023, 32(8): 086101.
[8]	Single crystal growth and electronic structure of Rh-doped Sr₃Ir₂O₇ Bingqian Wang(王冰倩), Shuting Peng(彭舒婷), Zhipeng Ou(欧志鹏), Yuchen Wang(王宇晨), Muhammad Waqas, Yang Luo(罗洋), Zhiyuan Wei(魏志远), Linwei Huai(淮琳崴), Jianchang Shen(沈建昌), Yu Miao(缪宇), Xiupeng Sun(孙秀鹏), Yuewei Yin(殷月伟), and Junfeng He(何俊峰). Chin. Phys. B, 2023, 32(8): 087108.
[9]	Multiple surface states, nontrivial band topology, and antiferromagnetism in GdAuAl₄Ge₂ Chengcheng Zhang(张成成), Yuan Wang(王渊), Fayuan Zhang(张发远), Hongtao Rong(戎洪涛), Yongqing Cai(蔡永青), Le Wang(王乐), Xiao-Ming Ma(马小明), Shu Guo(郭抒), Zhongjia Chen(陈仲佳), Yanan Wang(王亚南), Zhicheng Jiang(江志诚), Yichen Yang(杨逸尘), Zhengtai Liu(刘正太), Mao Ye(叶茂), Junhao Lin(林君浩), Jiawei Mei(梅佳伟), Zhanyang Hao(郝占阳), Zijuan Xie(谢子娟), and Chaoyu Chen(陈朝宇). Chin. Phys. B, 2023, 32(7): 077401.
[10]	Critical behavior in the epitaxial growth of two-dimensional tellurium films on SrTiO₃ (001) substrates Haimin Zhang(张海民), Dezhi Song(宋德志), Fuyang Huang(黄扶旸), Jun Zhang(仉君), and Ye-Ping Jiang(蒋烨平). Chin. Phys. B, 2023, 32(6): 066802.
[11]	Flat band in hole-doped transition metal dichalcogenide observed by angle-resolved photoemission spectroscopy Zilu Wang(王子禄), Haoyu Dong(董皓宇), Weichang Zhou(周伟昌), Zhihai Cheng(程志海), and Shancai Wang(王善才). Chin. Phys. B, 2023, 32(6): 067103.
[12]	Two-dimensional CrP₂ with high specific capacity and fast charge rate for lithium-ion battery Xiaoyun Wang(王晓允), Tao Jing(荆涛), and Dongmei Liang(梁冬梅). Chin. Phys. B, 2023, 32(6): 067102.
[13]	Prediction of LiCrTe₂ monolayer as a half-metallic ferromagnet with a high Curie temperature Li-Man Xiao(肖丽蔓), Huan-Cheng Yang(杨焕成), and Zhong-Yi Lu(卢仲毅). Chin. Phys. B, 2023, 32(5): 057505.
[14]	Predicting novel atomic structure of the lowest-energy Fe_nP_13-n (n=0-13) clusters: A new parameter for characterizing chemical stability Yuanqi Jiang(蒋元祺) and Ping Peng(彭平). Chin. Phys. B, 2023, 32(4): 047102.
[15]	High-temperature ferromagnetism and strong π-conjugation feature in two-dimensional manganese tetranitride Ming Yan(闫明), Zhi-Yuan Xie(谢志远), and Miao Gao(高淼). Chin. Phys. B, 2023, 32(3): 037104.

[1]	HUANG MAO (黄矛), LIU KE-LING (刘克玲). NON-BOLTZMANN ENERGY LEVEL DISTRIBUTIONS OF ARGON ATOMS IN THE INDUCTIVELY COUPLED ARGON PLASMA[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(1): 11 -18 .
[2]	FAN WEI-JUN (范卫军), XIA JIAN-BAI (顾宗权), GU ZONG-QUAN (夏建白), LI GUO-HUA (李国华). FIRST-PRINCIPLE SELF-CONSISTENT PSEUDOPOTENTIAL CALCULATION OF THE ELECTRONIC STRUCTURES OF SHORT-PERIOD (GaAs)_m(AlAs)_n SUPERLATT1CES[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(1): 45 -50 .
[3]	JIN YING (金鹰), ZHANG SHU-LIN (张树霖), QIN GUO-GANG (秦国刚), FAN YONG-LIANG (樊永良), ZHOU GOU-LIANG (周国良), YU MING-REN (俞鸣人). RAMAN SCATTERING INTENSITIES OF FOLDED LONGITUDINAL ACOUSTIC PHONONS IN Ge_xSi_1-x/Si SUPERLATTICES[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(2): 130 -137 .
[4]	WANG DA-CHUN (王大椿), DING XUN-LIANG (丁训良), YANG HUA (杨华), LUO PING-AN (罗平安). MASS ATTENUATION COEFFICIENTS FOR ELEMENTS MEASURED WITH CHARACTERISTIC X-RAYS FROM TARGETS EXCITED BY ENERGETIC PROTON[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(2): 138 -148 .
[5]	TIAN REN-HE (田人和), MANFRED FINK. THE BEAM TEMPERATURE AND ENERGY BROADENING OF A CHARGED-PARTICLE BEAM IN AN AXIALLY SYMMETRIC MAGNETIC FIELD[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(2): 86 -93 .
[6]	SUN XIAN-PING (孙献平), HU ZHI-LIN (胡志林), ZENG XI-ZHI (曾锡之), WANG QING-JI (王庆吉), ZHENG LE-MIN (郑乐民). THE 8²S_1/2→6²D EXCITATION TRANSFER OF RUBIDIUM ATOMS INDUCED BY COLLISIONS WITH GROUND-STATE RUBIDIUM AND HYDROGEN MOLECULES[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(3): 167 -172 .
[7]	LU HUA (陆华), WANG XIANG-DONG (王向东), K.MOTAI, T.HASHIZUME, T.SAKURAI. FI-STM STUDY OF HYDROGEN ADSORPTION ON Si(100) SURFACE[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(3): 191 -201 .
[8]	LI YI-JIE (李贻杰), XIONG GUANG-CHENG (熊光成), GAN ZI-ZHAO (甘子钊), REN CONG-XIN (任琮欣), CHEN GUO-LIANG (陈国梁), ZOU SHI-CHANG (邹世昌). SUPERCONDUCTING PROPERTIES AND STRUCTURAL PERFECTION OF EPITAXIAL YBa₂Cu₃O_7-x THIN FILMS[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(3): 211 -218 .
[9]	CHEN ANG (陈昂), ZHI YU (智宇), LI BIAO-RONG (李标荣), ZHANG XU-LI (张绪礼), TANG CHAO-QUN (唐超群), LI XIAO-HUA (李晓华), WANG SHAO-JIE (王少阶). POSITRON ANNIHILATION STUDY OF YBa₂(Cu_1-xSn_x)₃O_y SUPERCONDUCTORS[J]. Acta Physica Sinica (Overseas Edition), 1992, 1(3): 219 -223 .
[10]	PENG YU-FENG (彭玉峰), TANG JUN-XIONG (汤俊雄), WANG QING-JI (王庆吉). STUDY OF FARADAY ANOMALOUS DISPERSION SPECTRA OF THE HYPERFINE STRUCTURE OF Rb D₂ LINES[J]. Acta Physica Sinica (Overseas Edition), 1993, 2(1): 1 -8 .

Viewed

Full text

Abstract

Cited

Metrics
Related Articles

Absence of BCS-BEC crossover in FeSe0.45Te0.55 superconductor

Cite this article:

Online attention

Absence of BCS-BEC crossover in FeSe_0.45Te_0.55 superconductor