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TT: Fachverband Tiefe Temperaturen

TT 15: Frustrated Magnets - General 2 (joint session TT/MA)

TT 15.1: Vortrag

Montag, 16. März 2020, 15:00–15:15, HSZ 304

Quantum domain wall induced incommensurate magnetic phase in frustrated Ising model — •Zheng Zhou¹, Zheng Yan^1,2, Dong-Xu Liu³, Yan Chen^1,4, and Xue-Feng Zhang⁵ — ¹Department of Physics and State Key Laboratory of Surface Physics, Fudan University, Shanghai 200438, China — ²Department of Physics, The University of Hong Kong, Hong Kong, China — ³Department of Physics, Chongqing University, Chongqing, 401331, China — ⁴Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China — ⁵Department of Physics, and Center of Quantum Materials and Devices, Chongqing University, Chongqing, 401331, China

We study the AFM Ising model with transverse field h and NNN Ising interaction J′ on triangular lattice, which describes the magnet TmMgGaO₄. Between the known clock and stripe phase at weak and moderate J′, an incommensurate order may emerge due to the interplay between quantum fluctuation and geometrical frustration. In particular, the proliferation of quantum domain walls (DW) may stabilize such a novel phase. Numerical calculation of DW density and peaks of structure factor at certain positions provides evidence for this phase. Furthermore, we study its dynamical spectrum, which can be measured by neutron refraction. At a low h, we found a low-lying mode which agrees well with the behavior of DWs. At the h level of TmMgGaO₄, this mode merges with a high-lying mode corresponding to KT physics. We suggest that in materials with smaller splitting, distinct DW modes as strong evidence of this phase may be observed.