A first-principles-based computational tool for simulating phonons of magnetic random solid solutions including thermal magnetic fluctuations is developed. The method takes fluctuations of force constants due to magnetic excitations as well as due to chemical disorder into account. The developed approach correctly predicts the experimentally observed unusual phonon hardening of a transverse acoustic mode in Fe–Pd an Fe–Pt Invar alloys with increasing temperature. This peculiar behavior, which cannot be explained within a conventional harmonic picture, turns out to be a consequence of thermal magnetic fluctuations. The proposed methodology can be straightforwardly applied to a wide range of materials to reveal new insights into physical behaviors and to design materials through computation, which were not accessible so far.

开发了基于第一原理的计算工具，用于模拟包括热磁涨落的磁随机固溶体的声子。该方法考虑了由于磁激励以及由于化学无序所引起的力常数的波动。所开发的方法正确地预测了实验观察到的随温度升高而在Fe–Pd和Fe–Pt Invar合金中横向声模的异常声子硬化。这种特殊的行为是传统的谐波图无法解释的，它是热磁波动的结果。所提出的方法可以直接应用于各种材料，以揭示对物理行为的新见解，并可以通过计算来设计材料，这是迄今为止尚无法获得的。