摘要
文章结合中子散射和热力学测量研究了三角格子量子伊辛磁体TmMgGaO_(4)的磁关联行为在外加纵向磁场下的演变.实验发现,在中等强度的磁场下系统出现了一个量子涨落诱导的准平台相.该相的磁有序和自旋能隙表现出非单调的磁场和温度依赖关系,随着磁场的增大先变大后变小.在更高的外磁场下,量子涨落被大部分抑制后系统进入了一个无序相,自旋激发强度同时变弱.结合细致的半经典计算,该研究可以定量地理解量子涨落和阻挫伊辛相互作用之间的竞争作用所导致的上述新奇物理现象.
We report thermodynamic and neutron scattering measurements of the triangular-lattice quantum Ising magnet TmMgGaO_(4)in longitudinal magnetic fields.Our experiments reveal a quasi-plateau state induced by quantum fluctuations.This state exhibits an unconventional non-monotonic field and temperature dependence of the magnetic order and excitation gap.In the high field regime where the quantum fluctuations are largely suppressed,we observed a disordered state with coherent magnon-like excitations despite the suppression of the spin excitation intensity.Through detailed semi-classical calculations,we are able to understand these behaviors quantitatively from the subtle competition between quantum fluctuations and frustrated Ising interactions.
作者
秦亚媛
沈瑶
刘长乐
沃弘樑
高永豪
冯雨
张孝文
丁高峰
顾一卿
王奇思
申守栋
Helen C.Walker
Robert Bewley
Jianhui Xu
Martin Boehm
Paul Steffens
河村聖子
村井直樹
Astrid Schneidewind
童欣
陈钢
赵俊
Yayuan Qin;Yao Shen;Changle Liu;Hongliang Wo;Yonghao Gao;Yu Feng;Xiaowen Zhang;Gaofeng Ding;Yiqing Gu;Qisi Wang;Shoudong Shen;Helen C.Walker;Robert Bewley;Jianhui Xu;Martin Boehm;Paul Steffens;Seiko Ohira-Kawamura;Naoki Murai;Astrid Schneidewind;Xin Tong;Gang Chen;Jun Zhao(State Key Laboratory of Surface Physics and Department of Physics,Fudan University,Shanghai 200433,China;Condensed Matter Physics and Materials Science Department,Brookhaven National Laboratory,Upton,New York 11973,USA;Shanghai Qizhi Institute,Shanghai 200232,China;Institute of High Energy Physics,Chinese Academy of Sciences(CAS),Beijing 100049,China;Spallation Neutron Source Science Center,Dongguan 523803,China;Materials and Life Science Division,J-PARC Center,Tokai,Ibaraki 319-1195,Japan;Physik-Institut,Universität Zürich,Zürich CH-8057,Switzerland;ISIS Facility,Rutherford Appleton Laboratory,STFC,Chilton,Didcot,Oxon OX110QX,UK;Helmholtz-Zentrum Berlin für Materialien und Energie GmbH,Berlin D-14109,Germany;Institut Laue-Langevin,Grenoble 9,Cedex 38042,France;Jülich Centre for Neutron Science(JCNS)at Heinz Maier-Leibnitz Zentrum(MLZ),Forschungszentrum Jülich GmbH,Garching 85748,Germany;Department of Physics and HKU-UCAS Joint Institute for Theoretical and Computational Physics at Hong Kong,The University of Hong Kong,Hong Kong,China;Institute of Nanoelectronics and Quantum Computing,Fudan University,Shanghai 200433,China;Shanghai Research Center for Quantum Sciences,Shanghai 201315,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)
基金
supported by the Innovation Program of Shanghai Municipal Education Commission(2017–01-07–00-07-E00018)
the National Key R&D Program of the MOST of China(2016YFA0300203,2016YFA0300500,2016YFA0301001,and 2018YFE0103200)
the National Natural Science Foundation of China(11874119)
Shanghai Municipal Science and Technology Major Project(2019SHZDZX04)
the Hong Kong Research Grants Council(17303819 and 17306520)
supported by the National Natural Science Foundation of China(11875265)
the Scientific Instrument Developing Project of the Chinese Academy of Sciences(3He based neutron polarization devices)
the Institute of High Energy Physics
the Chinese Academy of Sciences。
