发表机构
University of Wisconsin-Madison（威斯康星大学麦迪逊分校）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究通过分子束外延和机械剥离制备单晶MnPtGa薄膜，利用褶皱实现应变调控，抑制140 K磁异常，为探测和调控竞争磁序提供了新平台。
AI 中文摘要
MnPtGa在中心对称的$P6_3/mmc$结构中承载竞争磁态，包括铁磁、倾斜反铁磁和自旋密度波（SDW）序，而相关的破缺反演结构则支持手性斯格明子。控制这种竞争推动了能够实现可调应变和对称性破缺的材料平台的发展，以及适用于超薄样品的SDW序探测手段。在此，我们展示了通过分子束外延在石墨烯/Ge(111)上生长并通过机械剥离释放的单晶MnPtGa薄膜。X射线和电子衍射证实了高晶体质量。SQUID磁强计揭示了零场冷却$dM/dT$中140 K的异常，该异常在剥离后持续存在，而时间分辨反射率显示电子弛豫时间中存在重合的峰，与假定的SDW能隙相关的准粒子声子瓶颈一致。有意的褶皱抑制了约140 K的磁异常，证明了对低温态的力学控制。这些结果确立了MnPtGa薄膜作为检测和应变调控竞争磁序的平台。
英文摘要
MnPtGa hosts competing magnetic states, including ferromagnetic, canted antiferromagnetic, and spin density wave (SDW) order in the centrosymmetric $P6_3/mmc$ structure, while a related inversion-broken structure supports chiral skyrmions. Controlling this competition motivates materials platforms that enable tunable strain and symmetry breaking, together with probes of SDW order compatible with ultrathin samples. Here, we demonstrate single crystalline MnPtGa membranes grown by molecular beam epitaxy on graphene/Ge(111) and released by mechanical exfoliation. X-ray and electron diffraction confirm high crystalline quality. SQUID magnetometry reveals a 140 K anomaly in the zero-field-cooled $dM/dT$ that persists after exfoliation, while time-resolved reflectivity shows a coincident peak in the electronic relaxation time consistent with a quasiparticle phonon bottleneck associated with a putative SDW gap. Intentional rippling suppresses the $\sim 140$ K magnetic anomaly, demonstrating mechanical control of the low-temperature state. These results establish MnPtGa membranes as a platform for detecting and strain-tuning competing magnetic orders.
