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....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.展开更多
基金supported by National Key Projects for Research and Development of China with Grant No. 2021YFA1400400the National Natural Science Foundation of China with Grants No. 12225407 and 12074174+2 种基金China Postdoctoral Science Foundation with Grants No. 2022M711569 and 2022T150315Jiangsu Province Excellent Postdoctoral Program with Grant No. 20220ZB5Fundamental Research Funds for the Central Universities
基金supported by National Key Projects for Research and Development of China with Grant No. 2021YFA1400400the National Natural Science Foundation of China with Grants No. 12225407 and 12074174+2 种基金China Postdoctoral Science Foundation with Grants No. 2022M711569 and 2022T150315Jiangsu Province Excellent Postdoctoral Program with Grant No. 20220ZB5Fundamental Research Funds for the Central Universities
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)+1 种基金the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20180006,BK20190436,and BK20200738)the Shanghai Sailing Program(Grant Nos.20YF1430600 and 21YF1429200)。
文摘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.
