Boson peaks are observed in glassy materials due to atom, spin, and strain disordered states that provide additional vibration modes at low temperatures. However, Boson peaks have not been observed in pure dipole disordered systems without structural disorder. Here, we report the observation of a Boson-peak-like hump in specific heat near 7 K in organic-inorganic hybrid crystal MA_{4}InCl_{7}(MA=CH_{3}NH_{3}). The energy barrier for unbonded Cl anions migration is extremely low, allowing that the migration persists down to low temperatures. The migration and the subsequent relaxation process induce a random change in its dipole, leading to the dipole disorder states. Our results show that MA_{4}InCl_{7} can be regarded as a dipole glass that can give rise to the Boson peak as well.

中文翻译：

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（CH_{3}NH_{3}）_ {4}InCl_{7} 中偶极子无序态诱导的玻色子峰样异常。


在玻璃材料中观察到玻色子峰，这是由于原子、自旋和应变无序状态在低温下提供额外的振动模式。然而，在没有结构无序的纯偶极子无序系统中尚未观察到玻色子峰。在这里，我们报告了在有机-无机杂化晶体 MA_{4}InCl_{7} （MA=CH_{3}NH_{3}） 中在 7 K 附近的比热中观察到的玻色子峰状驼峰。未键合 Cl 阴离子迁移的能垒极低，允许迁移持续到低温。迁移和随后的弛豫过程会引起其偶极子的随机变化，从而导致偶极子无序状态。我们的结果表明，MA_{4}InCl_{7} 也可以被视为可以产生玻色子峰的偶极子玻璃。