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arXiv · 1803.00688

Continuum excitation and pseudospin wave in quantum spin-liquid and quadrupole ordered states of Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$

Hiroaki Kadowaki·Mika Wakita·Björn Fåk·Jacques Ollivier·Seiko Ohira-Kawamura·Kenji Nakajima·Hiroshi Takatsu·Mototake Tamai
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Abstract

The ground states of the frustrated pyrochlore oxide Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ have been studied by inelastic neutron scattering experiments. Three single-crystal samples are investigated; one shows no phase transition ($x=-0.007<x_{\text{c}}\sim -0.0025$), being a putative quantum spin-liquid (QSL), and the other two ($x=0.000, 0.003$) show electric quadrupole ordering (QO) below $T_{\text{c}} \sim 0.5$ K. The QSL sample shows continuum excitation spectra with an energy scale 0.1 meV as well as energy-resolution limited (nominally) elastic scattering. As $x$ is increased, pseudospin wave of the QO state emerges from this continuum excitation, which agrees with that of powder samples and consequently verifies good $x$ control for the present single crystal samples.

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Hiroaki Kadowaki, Mika Wakita, Björn Fåk, Jacques Ollivier, Seiko Ohira-Kawamura, Kenji Nakajima, Hiroshi Takatsu, Mototake Tamai. 2018-03-02. Continuum excitation and pseudospin wave in quantum spin-liquid and quadrupole ordered states of Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$. https://doi.org/10.7566/jpsj.87.064704

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