Order by Disorder and Energetic Selection of the Ground State in the XY Pyrochlore Antiferromagnet Er2Ti2O7. An Inelastic Neutron Scattering Study

Abstract

Examples of materials where an "order by disorder" mechanism is at play to select a particular ground state are scarce. It has recently been proposed, however, that the antiferromagnetic XY pyrochlore Er2Ti2O7, reveals a most convincing case of this mechanism. Observation of a spin gap at zone centers has recently been interpreted as a corroboration of this physics. In this paper, we argue, however, that the anisotropy generated by the interaction-induced admixing between the crystal-field ground and excited levels provides for an alternative mechanism. It especially predicts the opening of a spin gap of about 15 micro-eV, which is of the same order of magnitude as the one observed experimentally. We report new high resolution inelastic neutron scattering data which can be well understood within this scenario.

This version corrects a mistake on the numerical values of the exchange couplings $J$ in relation to the published version

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Cited by in corpus (34)

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• Theory of multiple--phase competition in pyrochlore magnets with anisotropic exchange, with application to Yb2Ti2O7, Er2Ti2O7 and Er2Sn2O7
• Living on the edge : ground-state selection in quantum spin-ice pyrochlores
• Frustration and anisotropic exchange in ytterbium magnets with edge-shared octahedra
• Fluctuations and all-in$-$all-out ordering in dipole-octupole Nd2Zr2O7
• Experimental Insights into Ground State Selection of Quantum XY Pyrochlores
• Spin dynamics in the presence of competing ferro- and antiferro-magnetic correlations in Yb2Ti2O7
• Pseudo-Goldstone gaps and order-by-quantum-disorder in frustrated magnets
• Crystal field parameters of the rare earth pyrochlores $R_2$Ti${}_2$O${}_7$ ($R$ = Tb, Dy, Ho)
• Antiferro-quadrupolar correlations in the quantum spin ice candidate Pr2Zr2O7
• Structural and Magnetic Investigations of Single-Crystals of the Neodymium Zirconate Pyrochlore, Nd2Zr2O7
• Single-ion properties of the $S_{eff}$ = 1/2 XY antiferromagnetic pyrochlores, Na$A^{\prime }$Co${}_2$F${}_7$ ($A^{\prime }=$ Ca${}^{2+}$, Sr${}^{2+}$)
• Ground state selection in XY pyrochlore antiferromagnets R${}_2$Ge${}_2$O${}_7$ (R = Er, Yb)
• Crystal field Hamiltonian and anisotropy in KErSe2 and CsErSe2
• Order by virtual crystal field fluctuations in pyrochlore XY antiferromagnets
• Effect of Chemical Pressure on the Crystal Electric Field States of Erbium Pyrochlore Magnets
• XY Antiferromagnetic Ground State in the Effective S=1/2 Pyrochlore Yb2Ge2O7
• Order-by-disorder near criticality in $XY$ pyrochlore magnets
• Dynamic quantum kagome ice
• Fluctuation-Driven Selection at Criticality in a Frustrated Magnetic System: the Case of Multiple-k Partial Order on the Pyrochlore Lattice
• Order Induced by Dilution in Pyrochlore XY Antiferromagnets
• Frustrated magnetism in the Heisenberg pyrochlore antiferromagnets $A$Yb${}_2$$X$${}_4$ ($A$ = Cd, Mg, $X$ = S, Se)
• Pseudo-Goldstone modes and dynamical gap generation from order-by-thermal-disorder
• Magnetic dilution and domain selection in the XY pyrochlore antiferromagnet Er${}_2$Ti${}_2$O${}_7$
• Low-field behavior of an XY pyrochlore antiferromagnet: emergent clock anisotropies
• Field induced phase diagram of the XY pyrochlore antiferromagnet Er${}_2$Ti${}_2$O${}_7$
• Experimental evidence for field induced emergent clock anisotropies in the XY pyrochlore Er${}_2$Ti${}_2$O${}_7$
• Order-by-disorder without quantum zero-point fluctuations in the pyrochlore Heisenberg ferromagnet with Dzyaloshinskii-Moriya interactions
• Multi-phase competition in quantum $XY$ pyrochlore antiferromagnet CdYb${}_2$Se${}_4$: zero and applied magnetic field study
• Exchange interactions in two-state systems: rare earth pyrochlores
• Magnetic field tuning of crystal field levels and vibronic states in Spin-ice Ho${}_2$Ti${}_2$O${}_7$ observed in far-infrared reflectometry
• Quantum Rotor Theory of Systems of Spin-2 Bosons
• Observation of magnetic fragmentation in spin ice