论文标题
Pyrochore Magnet tb $ _ {2+x} $ ti $ _ {2-x} $ o $ $ $ _ {7+y} $
Vibronic collapse of ordered quadrupolar ice in the pyrochore magnet Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$
论文作者
论文摘要
虽然沮丧的pyrochlore tb $ _ {2+x} $ ti $ _ {2-x} $ o $ $ _ {7+y} $在实验和理论上已经研究了二十多年来，但对这个非常规定的国家没有确定的描述。使用基于同步加速器的THZ光谱与量子数值模拟结合使用，我们突出了两个先前无关的特征之间的重要联系：遵循冰规则的四极级订单以及以杂交TB $^{3+} $ Crystal-Field Field和Phonon Modes和Phonon Modes的形式存在强磁弹性耦合。这种所谓的振动过程的大小涉及四极度自由度，它显着取决于小的外偏材料计$ x $，并偏爱四倍体之间的全面相关性。该机制与远距离有序的四极冰竞争，并且对于略有不同的化学计量，能够破坏它的稳定性。
While the spin liquid state in the frustrated pyrochlore Tb$_{2+x}$Ti$_{2-x}$O$_{7+y}$ has been studied both experimentally and theoretically for more than two decades, no definite description of this unconventional state has been achieved. Using synchrotron based THz spectroscopy in combination with quantum numerical simulations, we highlight a significant link between two previously unrelated features: the existence of a quadrupolar order following an ice rule and the presence of strong magneto-elastic coupling in the form of hybridized Tb$^{3+}$ crystal-field and phonon modes. The magnitude of this so-called vibronic process, which involves quadrupolar degrees of freedom, is significantly dependent on small off-stoichiometry $x$ and favors all-in all-out like correlations between quadrupoles. This mechanism competes with the long range ordered quadrupolar ice, and for slightly different stoichiometry, is able to destabilize it.
