Abstract Triglycine sulfate (NH2CH2COOH)3⋅H2SO4, (TGS) has attracted much attention because it exhibits excellent ferroelectricity below the Curie temperature. Although TGS is composed of glycine and sulfuric acid, which are achiral molecules, it forms chiral crystals below the Curie temperature. Ferroelectric domain observations and polarization-electric field hysteresis loop measurements showed that TGS polarity become preferred after a small amount of doping with enantiomeric alanine. It has been confirmed that the preferred polarity appears when the internal bias electric field, caused by alanine doping, is larger than the coercive field. Furthermore, X-ray crystal structure analysis has revealed that L-alanine-doped TGS (LATGS) and D-alanine-doped TGS (DATGS) with the nominal amount of alanine above 50 mol% exhibited great preferences for either chirality, although the alanine content in the crystal was too low to be detected; alanine was a “ghost”. Correlation between the polarity and chirality, thus the “absolute polarity”, of LATGS and DATGS were identified, and the preferences induced by the alanine ghost were noted. We have found that the chirality of TGS grown from achiral molecules can be preferred using an extremely simple method; doping with a tiny amount of alanine.

中文翻译：

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丙氨酸鬼魂对硫酸三甘氨酸晶体中极性和手性的偏好

摘要 三甘氨酸硫酸盐 (NH2CH2COOH)3⋅H2SO4, (TGS) 因其在居里温度以下表现出优异的铁电性而备受关注。虽然TGS由非手性分子甘氨酸和硫酸组成，但它在居里温度以下形成手性晶体。铁电畴观察和极化电场磁滞回线测量表明，在少量掺杂对映体丙氨酸后，TGS 极性成为首选。已经证实，当由丙氨酸掺杂引起的内部偏置电场大于矫顽场时，优选极性出现。此外，X 射线晶体结构分析表明，标称量高于 50 mol% 的 L-丙氨酸掺杂 TGS (LATGS) 和 D-丙氨酸掺杂 TGS (DATGS) 表现出对任一手性的极大偏好，尽管晶体太低而无法检测到；丙氨酸是一种“幽灵”。确定了 LATGS 和 DATGS 的极性和手性之间的相关性，从而确定了“绝对极性”，并注意到了由丙氨酸鬼引起的偏好。我们发现使用一种极其简单的方法可以优选从非手性分子生长的 TGS 的手性；掺杂少量丙氨酸。并注意到由丙氨酸鬼引起的偏好。我们发现使用一种极其简单的方法可以优选从非手性分子生长的 TGS 的手性；掺杂少量丙氨酸。并注意到由丙氨酸鬼引起的偏好。我们发现使用一种极其简单的方法可以优选从非手性分子生长的 TGS 的手性；掺杂少量丙氨酸。