Magnetic Monopole Condensation Transition out of Quantum Spin Ice
Speaker
Prof. Gang Chen
Department of Physics, Fudan University
Abstract

We study the proximate magnetic orders and the related quantum phase transition out of quantum spin ice (QSI). We apply the electromagnetic duality of the compact quantum electrodynamics to analyze the condensation of the magnetic monopoles for QSI. The monopole condensation transition represents an unconventional quantum criticality with unusual scaling laws. The magnetic monopole condensation leads to the magnetic states that belong to the “2-in 2-out” spin ice manifold and generically have an enlarged magnetic unit cell. We demonstrate that the antiferromagnetic state with the ordering wavevector Q = 2p(001) is proximate to QSI while the ferromagnetic state with the ordering wavevector Q = (000) is not proximate to QSI. This implies that if there exists a direct transition from QSI to the ferromagnetic state, the transition must be strongly first order. We apply the theory to the puzzling experiments on two pyrochlore systems Pr2Ir2O7 and Yb2Ti2

About the Speaker

陈钢,2004中国科学技术大学学士毕业并获中科大本科生最高荣誉郭沫若奖学金,2010美国加州大学圣芭芭拉分校物理系博士,师从Leon Balents 教授at Kavli Institute for Theoretical Physics。2010年8月至2013年9月期间在美国科罗拉多大学Boulder分校物理系及JILA作博士后研究工作 (Postdoc Fellow under Michael Hermele, Leo Radzihovsky, Ana Maria Rey), 2013年10月至2015年3月期间加拿大多伦多大学物理系博士后。2015年4月至今在复旦大学物理学系任教。陈刚教授研究领域:理论凝聚态物理。研究横跨凝聚态的数个子领域,包含比如原子分子光学物理、量子材料、物质的奇异态以及拓扑态等等。总的来说是关注于凝聚态体系的量子性质,研究各种新奇的量子态,量子阻挫磁体,量子自旋冰,强自旋轨道耦合体系,关联电子体系,维尔半金属,拓扑绝缘体,各种量子材料包括过渡金属氧化物界面,阻挫磁体,准一维体系,铱氧化物,镍氧化物磁性,铁基超导,稀土金属磁体,巡游阻挫等等,着力于在实验体系中找到各种新奇的量子态。同时也关心冷原子体系中的独特的量子多体问题以及相关的量子模拟。 

 

Date&Time
2015-11-18 4:00 PM
Location
Room: A303 Meeting Room
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