标题： 设计反铁磁体中的自旋驱动多铁性材料 显示英文标题

标题： Designing Spin-driven Multiferroics in Altermagnets

摘要： 自旋驱动的多铁材料表现出强磁电耦合，在磁场下显示出显著的极化变化，但这些效应通常仅限于高Z磁绝缘体，其电子极化较低。 在本工作中，我们引入了反铁磁体作为在低Z系统中实现强磁电耦合的有前途的平台，具有显著的极化。 这种大极化是通过一种利用类似海森堡交换应变机制的设计原理产生的，消除了对自旋-轨道耦合（SOC）的依赖。 这种方法使来自反铁磁绝缘体的克雷默斯简并反铁磁相能够在没有自旋分裂的情况下实现显著的极化，为调节自旋分裂现象提供了一个灵活的平台。 通过第一性原理模拟和有效的朗道-金兹伯格哈密顿量，我们证明LiMnO2家族和应变RuF4家族的材料可以实现超过1.0{\mu }C/cm2的极化值，比SOC驱动的多铁材料高出一个数量级。 此外，它们的磁电耦合强度比传统多铁材料和由SOC驱动的多铁材料强一到两个数量级。 显示英文摘要

摘要： Spin-driven multiferroics exhibit strong magnetoelectric coupling, with notable polarization changes under a magnetic field, but these effects are usually limited to high-Z magnetic insulators with low electronic polarization. In this work, we introduce altermagnets as a promising platform for achieving strong magnetoelectric coupling in low-Z systems with substantial polarization. This large polarization arises from a design principle that utilizes the Heisenberg-like exchange striction mechanism, eliminating the reliance on spin-orbit coupling (SOC). This approach enables the Kramers-degenerate antiferromagnetic phase derived from altermagnetic insulators to achieve substantial polarization without spin splitting, providing a flexible platform for regulating spin-splitting phenomena. Through first-principles simulations and an effective Landau-Ginzburg Hamiltonian, we demonstrate that materials in the LiMnO2 family and strained RuF4 family can achieve polarization values exceeding 1.0 {\mu}C/cm2, an order of magnitude larger than those found in SOC-driven multiferroics. Moreover, their magnetoelectric coupling is one to two orders of magnitude stronger than that observed in conventional multiferroics and those driven by SOC.