We report a definitive evidence that germanium isotope effect triggers a noticeable cage distortion in n-type Ba₈Ga₁₆Ge₃₀ (BGG) with complete substitution of isotope Ge-76. Further extended X-ray absorption fine structure technique reflects a large disorder in the cages of the sample, although no accompanying obvious changing in distance of Ge-Ga/Ge is demonstrated. Hence, we suggest that the cumulative cage distortion originates from the variation of bond angle instead of bond length. Moreover, the intensive electron-phonon scattering is dominated by the isotope effect. These findings highlight atomic isotope engineering for modifying crystal structure and possibly even thermoelectric performance.

我们报告了一个确定的证据，锗同位素效应在完全取代同位素Ge-76的n型Ba ₈ Ga ₁₆ Ge ₃₀（BGG）中触发了明显的笼形畸变。进一步扩展的X射线吸收精细结构技术反映了样品笼中的较大紊乱，尽管没有证明伴随着Ge-Ga / Ge距离的明显变化。因此，我们建议累积的笼形畸变起源于键角的变化，而不是键长的变化。而且，强电子-声子散射主要受同位素效应的影响。这些发现突显了用于改变晶体结构甚至可能改变热电性能的原子同位素工程。