We report thermodynamic and neutron scattering measurements of the triangular-lattice quantum Ising magnet TmMgGaO4 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 fluc-tuations 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 lsing interactions.

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,Universit(a)t Zürich,Zürich CH-8057,Switzerland;ISIS Facility,Rutherford Appleton Laboratory,STPC,Chilton,Didcot,Oxon OX110QX,UK;Helmholtz-Zentrum Berlin für Materialien und Energie GmbH,Berlin D-14109,Germany;Institut Laue-Langevin,Grenoble;Cedex 38042,France;Heinz Maier-Leibnitz Zentrum (MLZ),Technische Universit(a)t München,Garching 85748,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;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China;Institute of Nanoelectronics and Quantum Computing,Fudan University,Shanghai 200433,China;Shanghai Research Center for Quantum Sciences,Shanghai 201315,China

科学通报（英文版）

[1]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-.Field-tuned quantum effects in a triangular-lattice Ising magnet)[J].科学通报（英文版）,2022(01):38-44

TmMgGaO4,tuations,lsing

Field,tuned,quantum,effects,triangular,lattice,Ising,We,report,thermodynamic,neutron,scattering,measurements,longitudinal,magnetic,fields,Our,experiments,reveal,quasi,plateau,state,induced,by,fluctuations,This,exhibits,unconventional,monotonic,temperature,dependence,gap,In,high,regime,where,are,largely,suppressed,observed,disordered,coherent,magnon,like,excitations,despite,suppression,spin,intensity,Through,detailed,semi,classical,calculations,able,understand,these,behaviors,quantitatively,from,subtle,competition,between,frustrated,interactions

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