We report a comprehensive high-pressure study, up to 21.1 GPa, on the antiferromagnetic topological insulator EuSn₂As₂ achieved through synchrotron X-ray diffraction, Raman scattering, electrical resistance, magnetic resistance, and Hall transport measurements in combination with first-principles calculations. The Néel temperatures determined from resistance are increased from (24±1) to (77±8) K under pressure, which is a result of enhanced magnetic exchange couplings between Eu²⁺ ions yielded by our first-principles calculations. The negative magnetoresistance of EuSn₂As₂ persists to higher temperatures accordingly. However, the enhancement of the observed Néel temperatures deviates from the calculations above 10.0 GPa. In addition, the magnitude of the magnetoresistance, Hall coefficients, and charge carrier densities show abrupt changes between 6.9 and 10.0 GPa. The abrupt changes likely originate from a pressure-induced valence change of Eu ions from a divalent state to a divalent and trivalent mixed state or are related to the structural transition revealed by Raman scattering measurements. Our results provide insight into magnetism variation in EuSn₂As₂ and similar antiferromagnetic topological insulators under pressure.

我们报告了对反铁磁拓扑绝缘体 EuSn ₂ As ₂进行的高达 21.1 GPa 的全面高压研究，该研究通过同步加速器 X 射线衍射、拉曼散射、电阻、磁阻和霍尔输运测量结合第一性原理实现计算。在压力下，由电阻确定的 Néel 温度从 (24±1) K 增加到 (77±8) K，这是我们的第一性原理计算得出的Eu ²⁺离子之间增强的磁交换耦合的结果。EuSn ₂ As ₂的负磁阻相应地持续到更高的温度。然而，观察到的 Néel 温度的增强偏离了 10.0 GPa 以上的计算。此外，磁阻的大小、霍尔系数和电荷载流子密度在 6.9 和 10.0 GPa 之间显示出突然变化。突然变化可能源于压力引起的 Eu 离子从二价态到二价和三价混合态的价态变化，或者与拉曼散射测量揭示的结构转变有关。我们的结果提供了对 EuSn ₂ As ₂和类似反铁磁拓扑绝缘体在压力下的磁性变化的洞察。