Department of Physics , University of Washington , Seattle , Washington 98195 , United States.
Department of Physics and Center of Theoretical and Computational Physics , University of Hong Kong , Hong Kong , China.
Nano Lett. 2019 Feb 13;19(2):915-920. doi: 10.1021/acs.nanolett.8b04160. Epub 2019 Jan 10.
Atomically thin chromium triiodide (CrI) has recently been identified as a layered antiferromagnetic insulator, in which adjacent ferromagnetic monolayers are antiferromagnetically coupled. This unusual magnetic structure naturally comprises a series of antialigned spin filters, which can be utilized to make spin-filter magnetic tunnel junctions with very large tunneling magnetoresistance (TMR). Here we report voltage control of TMR formed by four-layer CrI sandwiched by monolayer graphene contacts in a dual-gated structure. By varying the gate voltages at fixed magnetic field, the device can be switched reversibly between bistable magnetic states with the same net magnetization but drastically different resistance (by a factor of 10 or more). In addition, without switching the state, the TMR can be continuously modulated between 17,000% and 57,000%, due to the combination of spin-dependent tunnel barrier with changing carrier distributions in the graphene contacts. Our work demonstrates new kinds of magnetically moderated transistor action and opens up possibilities for voltage-controlled van der Waals spintronic devices.
原子层状三碘化铬（CrI）最近被确定为一种层状反铁磁绝缘体，其中相邻的铁磁单层通过反铁磁耦合。这种不寻常的磁结构自然包含一系列反平行的自旋滤波器，可用于制造具有非常大隧穿磁电阻（TMR）的自旋滤波器磁隧道结。在这里，我们报告了在双栅结构中由单层石墨烯接触夹在四层 CrI 之间形成的 TMR 的电压控制。通过在固定磁场下改变栅极电压，该器件可以在具有相同净磁化强度但电阻截然不同的双稳态磁状态之间可逆切换（相差 10 倍或更多）。此外，由于自旋相关的隧道势垒与石墨烯接触中载流子分布的变化相结合，无需切换状态，TMR 就可以在 17000%和 57000%之间连续调制。我们的工作展示了新型磁调制晶体管的作用，并为电压控制的范德瓦尔斯自旋电子器件开辟了可能性。
