德国马克斯·普朗克固体化学物理研究所Stanis?aw Ga?eski团队通过声子的电子吸收实现低密度金属热输运中的巨量子振荡。2025年3月5日，《美国科学院院刊》发表了这一成果。
在强磁场中观察到的电导振荡是固体中电荷载流子量子动力学的一个显著表现。典型金属中的大电荷载流子密度设定了电导率和热导率的振荡尺度，这是费米面的特征。在半金属中，低电荷载流子密度下的热输运预计将以声子为主，但一些实验观察到热输运中的巨大量子振荡。这就提出了一个问题，即是否存在一种总体机制，导致在声子主导的半金属中存在相当大的振荡。
在这项工作中，研究组证明了这种机制的存在。它依赖于当只有几个朗道能级被填充时，电子允许声子散射的特殊相空间。他们对狄拉克半金属ZrTe5的测量通过观察明显的热量子振荡来支持这一违反直觉的机制，因为其在平行和横向于磁场的方向上以相似的幅度和相位发生。该相空间论证适用于所有低密度半金属，无论是否拓扑，包括石墨烯和铋。该工作表明，声子吸收可以通过其在纵向热输运上的印记来揭示自由度。
附：英文原文
Title: Giant quantum oscillations in thermal transport in low-density metals via electron absorption of phonons
Author: Bermond, Baptiste, Wawrzyńczak, Rafa, Zherlitsyn, Sergei, Kotte, Tommy, Helm, Toni, Gorbunov, Denis, Gu, Genda, Li, Qiang, Janasz, Filip, Meng, Tobias, Menges, Fabian, Felser, Claudia, Wosnitza, Joachim, Grushin, Adolfo, Carpentier, David, Gooth, Johannes, Gaeski, Stanisaw
Issue&Volume: 2025-3-5
Abstract: Oscillations of conductance observed in strong magnetic fields are a striking manifestation of the quantum dynamics of charge carriers in solids. The large charge carrier density in typical metals sets the scale of oscillations in both electrical and thermal conductivity, which characterize the Fermi surface. In semimetals, thermal transport at low-charge carrier density is expected to be phonon dominated, yet several experiments observe giant quantum oscillations in thermal transport. This raises the question of whether there is an overarching mechanism leading to sizable oscillations that survives in phonon-dominated semimetals. In this work, we show that such a mechanism exists. It relies on the peculiar phase-space allowed for phonon scattering by electrons when only a few Landau levels are filled. Our measurements on the Dirac semimetal ZrTe5 support this counterintuitive mechanism through observation of pronounced thermal quantum oscillations, since they occur in similar magnitude and phase in directions parallel and transverse to the magnetic field. Our phase-space argument applies to all low-density semimetals, topological or not, including graphene and bismuth. Our work illustrates that phonon absorption can be leveraged to reveal degrees of freedom through their imprint on longitudinal thermal transport.
DOI: 10.1073/pnas.2408546122
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2408546122