Field-tuned quantum effects in a triangular-lattice Ising magnet

The Shanghai alliance of multilingual researchers: Fudan University, Tongji University, Shanghai University of Finance and Economics, and Shanghai International Studies University, China

“…where ⟨i, j⟩ and ⟨⟨i, j⟩⟩ denote the nearest and nextnearest neighbors, respectively, and h is the energy corresponding to the effective intrinsic transverse field describing the splitting of the ground state quasi-doublet, as described with TFIM [12,13,[16][17][18]. A set of parameters can describe the neutron scattering data accurately: J 1 = 0.29(1) meV, J 2 = 0.018(2) meV, h = 1.13(2) meV, the calculated results reasonably agree with the experimental observations [Fig.…”

“…Two common scenarios, involving triangular lattices occupied by either Kramers or non-Kramers ions, have been extensively investigated to elucidate unconventional magnetic ground states. A well known example of the former case is the quantum spin liquid (QSL) material YbMgGaO 4 [3][4][5][6][7][8][9][10][11], while TmMgGaO 4 with the integer spin local moments could be approximately viewed as an example of the non-Kramers doublets [12][13][14][15][16]. Despite the successful introduction and description of the transverse field Ising model (TFIM) in TmMgGaO 4 , further examination and research are necessary to address fundamental questions regarding the nature of magnetic excitations in generic non-Kramers triangular-lattice magnets [13,14,17,18].…”

“…Inelastic neutron scattering (INS) illustrates a branch of dispersive excitation from 0.85 to 1.6 meV which is the first excited CEF state of Tm 3+ , indicating that a single-ion model can no longer describe the low-lying CEF excitations. A frequently used solution is to apply the transverse field Ising model (TFIM) on KTmSe 2 to explain the dispersive magnetic excitation by constructing a pseudospin S eff = 1/2 from the ground state quasi-doublet [12,13,[16][17][18]. The effective model successfully explains the dispersive magnetic excitation by introducing a transverse field perpendicular to the z axis, and provides a phase diagram that can include many different materials with similar Ising characters.…”

Imaging the Magnetic Anisotropy in Ultrathin Fe4GeTe2 with a Nitrogen-Vacancy Magnetometer

“…However, obtaining a quantitative description of their magnetic structures becomes increasingly complex and more challenging. To date, while the phase transition has been revealed, 19,20 the subtle magnetic anisotropy and the associated magnetization directions have not yet been fully identified. 21,22 The nitrogen vacancy (NV) center in diamond, which can directly sense the magnetic field, 23−28 may provide an ideal experimental platform for investigating the SRT and the associated magnetic anisotropy.…”

“…However, obtaining a quantitative description of their magnetic structures becomes increasingly complex and more challenging. To date, while the phase transition has been revealed, , the subtle magnetic anisotropy and the associated magnetization directions have not yet been fully identified. , …”