摘要
As one of the most promising Kitaev quantum-spin-liquid(QSL)candidates,α-RuCl_(3)has received a great deal of attention.However,its ground state exhibits a long-range zigzag magnetic order,which defies the QSL phase.Nevertheless,the magnetic order is fragile and can be completely suppressed by applying an external magnetic field.Here,we explore the evolution of magnetic excitations ofα-RuCl;under an in-plane magnetic field,by carrying out inelastic neutron scattering measurements on high-quality single crystals.Under zero field,there exist spin-wave excitations near the M point and a continuum near theΓpoint,which are believed to be associated with the zigzag magnetic order and fractional excitations of the Kitaev QSL state,respectively.By increasing the magnetic field,the spin-wave excitations gradually give way to the continuous excitations.On the verge of the critical fieldμ_(0)H_(c)=7.5 T,the former ones vanish and only the latter ones are left,indicating the emergence of a pure QSL state.By further increasing the field strength,the excitations near theΓpoint become more intense.By following the gap evolution of the excitations near theΓpoint,we are able to establish a phase diagram composed of three interesting phases,including a gapped zigzag order phase at low fields,possibly gapless QSL phase nearμ;H;,and gapped partially polarized phase at high fields.These results demonstrate that an in-plane magnetic field can driveα-RuCl;into a long-sought QSL state near the critical field.
作者
赵晓雪
冉柯静
王靖珲
鲍嵩
上官艳艳
黄振涛
廖俊波
张波
承舒凡
徐豪
王巍
董召阳
孟思勤
陆智伦
Shin-ichiro Yano
于顺利
李建新
温锦生
Xiaoxue Zhao;Kejing Ran;Jinghui Wang;Song Bao;Yanyan Shangguan;Zhentao Huang;Junbo Liao;Bo Zhang;Shufan Cheng;Hao Xu;Wei Wang;Zhao-Yang Dong;Siqin Meng;Zhilun Lu;Shin-ichiro Yano;Shun-Li Yu;Jian-Xin Li;Jinsheng Wen(National Laboratory of Solid State Microstructures and Department of Physics,Nanjing University,Nanjing 210093,China;School of Physical Science and Technology and ShanghaiTech Laboratory for Topological Physics,ShanghaiTech University,Shanghai 200031,China;School of Science,Nanjing University of Posts and Telecommunications,Nanjing 210023,China;Department of Applied Physics,Nanjing University of Science and Technology,Nanjing 210094,China;Helmholtz-Zentrum Berlin fur Materialien und Energie GmbH,Hahn-Meitner-Platz 1D-14109 Berlin,Germany;China Institute of Atomic Energy,Beijing 102413,China;School of Engineering and the Built Environment,Edinburgh Napier University,Edinburgh EH105DT,United Kingdom;National Synchrotron Radiation Research Center,Hsinchu 30077,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)
基金
supported by the National Key Research and Development Program of China(Grant No.2021YFA1400400)
the National Natural Science Foundation of China(Grant Nos.11822405,12074174,12074175,92165205,11904170,12004249,12004251,and 12004191)
the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20180006,BK20190436,and BK20200738)
the Shanghai Sailing Program(Grant Nos.20YF1430600 and 21YF1429200)。