Low Energy Electrodynamics of Novel Spin Excitations in the Quantum Spin Ice Yb${}_2$Ti${}_2$O${}_7$

Abstract

In condensed matter systems, the formation of long range order (LRO) with broken symmetry is often accompanied by new types of excitations. However, in many magnetic pyrochlore oxides, geometrical frustration suppresses conventional LRO while at the same time non-trivial spin correlations are observed. For such materials, a natural question to ask then is what is the nature of the excitations in this highly correlated state without broken symmetry? Frequently the application of a symmetry breaking field can stabilize excitations whose properties still reflect certain aspects of the anomalous state without long-range order. Here we report evidence of novel magnetic excitations in the quantum spin ice material Yb${}_2$Ti${}_2$O${}_7$, obtained from time-domain terahertz spectroscopy (TDTS). At large fields, both magnon and two-magnon-like excitations are observed in a $<$001$>$ directed magnetic field illustrating the stabilization of a field induced LRO state. The unique ability of TDTS to measure complex response functions allows a direct study of magnetic responses in different polarization channels, revealing the existence of an unusual left-hand polarized magnon. The g-factors of these excitations are dramatically enhanced in the low-field limit, showing a cross-over of these one- and two-magnon states into features consistent with quantum string-like excitations proposed to exist in quantum spin ice in a small $<$001$>$ applied field.

15 pages

References in corpus (6)

• Dirac Strings and Magnetic Monopoles in Spin Ice Dy2Ti2O7
• Lightly stuffed pyrochlore structure of single-crystalline Yb2Ti2O7 grown by the optical floating zone technique
• Is the Yb2Ti2O7 pyrochlore a quantum spin ice?
• Rods of Neutron Scattering Intensity in Yb2Ti2O7: Compelling Evidence for Significant Anisotropic Exchange in a Magnetic Pyrochlore Oxide
• Spin resonance in EuTiO3 probed by time-domain GHz ellipsometry
• Mapping the first order magnetic transition in Yb${}_2$Ti${}_2$O${}_7$

Cited by in corpus (5)

• Spinon magnetic resonance of quantum spin liquids
• Magnetic Excitations in the Ground State of $\mathrm{Y}{\mathrm{b}}_2\mathrm{T}{\mathrm{i}}_2{\mathrm{O}}_7$
• Epitaxial stabilization of (111)-oriented frustrated quantum pyrochlore thin films
• Magnetic terahertz resonances above the Néel temperature in the frustrated kagome antiferromagnet averievite
• Inertial effects in systems with magnetic charge