6 月 26 日 钟山论坛邀请报告—杜兰大学毛志强教授
报告人： Z. Q. Mao
Department of Physics and Engineering Physics
Tulane University
题目：Interplay between magnetism and superconductivity in iron chalcogenides
日期：6 月 26 日（周四）上午 10:30
地点：唐仲英楼 B501
摘要：
The interplay between magnetism and superconductivity in Fe-based superconductor
systems is currently a subject of intense studies. The iron chalcogenide Fe1+y(Te1-xSex) is of
particular interest due to its unique magnetic properties. While the parent compound Fe1+yTe
shows antiferromagnetism with (,0) in-plane magnetic wave vector [1], the optimally doped
sample displays superconductivity with (,) spin resonance [2]. This contrasts with iron
pnictides in which both the parent compound’s antiferromagnetism [3-4] and the doped
samples’ superconducting (SC) spin resonance [5-7] are characterized by the in-plane Fermi
surface nesting wave vector Qn = (,). The evolution from (,0) magnetism to
superconductivity with (,) spin resonance in iron chalcogenides is associated with
coexistence of magnetic correlations at (,0) and (,) [8]. The other remarkable difference
between iron chalcogenide and iron pnictide superconductors is their phase diagrams. In iron
pnictides, bulk superconductivity either emerges immediately following suppression of
long-range (,) antiferromagnetic (AFM) order [9-10], or coexists with it in a particular
composition range [11-14]. In contrast, in iron chalcogenides, bulk superconductivity does
not appear immediately following the suppression of long-range (,0) AFM order. Instead, an
intermediate phase with weak charge carrier localization appears between AFM order and
bulk superconductivity for 0.09 < x < 0.3 [8]. In this talk, I will first present an overview on
the results summarized above and then introduce our recent studies on the coupling between
electronic and magnetic properties in this system [8,15]. I will show the doping dependences
of Sommerfeld coefficient , Hall coefficient RH and Hall angle as well as their relations with
superconductivity [15]. The origin of superconductivity suppression and charge carrier
localization in the underdoped region will be discussed in terms of these experimental results.
References:
[1] W. Bao et al., Phys. Rev. Lett 102, 247001 (2009).
[2] Y. Qiu et al., Phys. Rev. Lett 103, 067008 (2009).
[3] C. de la Cruz et al., Nature 453, 899 (2008).
[4] Q. Huang et al., Phys. Rev. Lett 101, 257003 (2008).
[5] A. D. Christianson et al., Nature 456, 930 (2008).
[6] M. D. Lumsden et al., Phys. Rev. Lett 102, 107005 (2009).
[7] S. Chi et al., Phys. Rev. Lett 102, 107006 (2009).
[8] T. J. Liu et al., Nat. Mater. 9, 718 (2010).
[9] J. Zhao et al., Nat. Mater. 7, 953 (2008).
[10] H. Luetkens et al., Nat. Mater. 8, 305 (2009).
[11] A. J. Drew et al., Nat. Mater. 8, 310 (2009).
[12] H. Chen et al., Europhys. Lett. 85, 17006 (2009).
[13] J.-H. Chu et al., Phys. Rev. B 79, 014506 (2009).
[14] S. Nandi et al., Phys. Rev. Lett 104, 057006 (2010).
[15] J. Hu et al., Phys. Rev. B 88, 094505 (2013).
报告人简介：毛志强，1987 年毕业于南京师范大学获得学士学位，1992 年于中国科学技术
大学获得物理学博士学位后留校工作。1997 年到 2002 年先后在日本京都大学和美国宾州州
立大学从事博士后研究。2002 年加入杜兰大学物理系。 现为杜兰大学物理系主任，Nicholas
J. Altiero 名誉教授。他的研究领域主要包括强关联体系钙钛矿结构钌氧化物的奇异量子效应
以及铁基超导体。发表包括 Nature, Science, Nature materials, PRL 等重要文章 234 篇，H 因
子 36。 毛志强教授 2005 年获 Tulane 大学校长奖（此奖授予每年度最杰出的在 Tulane 大学
工作的青年学者，每年度仅一名）
，同年获美国 Research Corporation 基金会 Cottrell 学者奖
（全美每年 13 人），2007 年获美国自然科学基金委员会 Career 奖。2011 年获得 Nicholas J.
Altiero 荣誉教授。