Bhoi Dilip, Gouchi Jun, Hiraoka Naoka, Zhang Yufeng, Ogita Norio, Hasegawa Takumi, Kitagawa Kentaro, Takagi Hidenori, Kim Kee Hoon, Uwatoko Yoshiya
The Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
Department of Physics, Graduate School of Sciences, University of Tokyo, Tokyo 113-0033, Japan.
Phys Rev Lett. 2021 Nov 19;127(21):217203. doi: 10.1103/PhysRevLett.127.217203.
A complex interplay of different energy scales involving Coulomb repulsion, spin-orbit coupling, and Hund's coupling energy in 2D van der Waals (vdW) material produces a novel emerging physical state. For instance, ferromagnetism in vdW charge transfer insulator CrGeTe_{3} provides a promising platform to simultaneously manipulate the magnetic and electrical properties for potential device implementation using few nanometers thick materials. Here, we show a continuous tuning of magnetic and electrical properties of a CrGeTe_{3} single crystal using pressure. With application of pressure, CrGeTe_{3} transforms from a ferromagnetic insulator with Curie temperature T_{C}∼66 K at ambient condition to a correlated 2D Fermi metal with T_{C} exceeding ∼250 K. Notably, absence of an accompanying structural distortion across the insulator-metal transition (IMT) suggests that the pressure induced modification of electronic ground states is driven by electronic correlation furnishing a rare example of bandwidth-controlled IMT in a vdW material.
二维范德华(vdW)材料中涉及库仑排斥、自旋轨道耦合和洪德耦合能的不同能量尺度之间的复杂相互作用产生了一种新出现的物理状态。例如,vdW电荷转移绝缘体CrGeTe₃中的铁磁性为使用几纳米厚的材料同时操纵磁学和电学性质以实现潜在器件应用提供了一个有前景的平台。在此,我们展示了利用压力对CrGeTe₃单晶的磁学和电学性质进行连续调节。随着压力的施加,CrGeTe₃在环境条件下从具有居里温度Tc ∼ 66 K的铁磁绝缘体转变为Tc超过 ∼ 250 K的关联二维费米金属。值得注意的是,在绝缘体 - 金属转变(IMT)过程中没有伴随的结构畸变,这表明压力诱导的电子基态变化是由电子关联驱动的,这为vdW材料中带宽控制的IMT提供了一个罕见的例子。