Single-valley quantum Hall ferromagnet in a dilute MgxZn1-xO/ZnO strongly correlated two-dimensional electron system
Single-valley quantum Hall ferromagnet in a dilute MgxZn1-xO/ZnO strongly correlated two-dimensional electron system
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DOI：
10.1103/physrevb.85.075302
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发表时间：
2012-02-03
影响因子：
3.7
通讯作者：
Kawasaki, M.
中科院分区：
文献类型：
--
作者：
Kozuka, Y.;Tsukazaki, A.;Kawasaki, M.
我们研究了限制在Mg_xZn_(1-x)O/ZnO异质界面的二维稀疏电子的自旋极化率(g*m*)。磁输运测量表明，g*m*增加了四倍，主要是朗德g因子的增加。G因子的增强导致电子气的铁磁不稳定性，这是由急剧的电阻尖峰所证明的。在高磁场下，大的g*m*导致全自旋极化，我们发现在半整数填充因子附近的电阻突然增加，伴随着分数量子霍尔态的完全消失。由于它的大有效质量和高的电子迁移率，我们的结果表明，氧化锌2D系统是研究QH区电子关联效应的理想材料。
We investigate the spin susceptibility (g*m*) of dilute two-dimensional (2D) electrons confined at the MgxZn1-xO/ZnO heterointerface. Magnetotransport measurements show a four-fold enhancement of g*m*, dominated by the increase in the Lande g-factor. The g-factor enhancement leads to a ferromagnetic instability of the electron gas as evidenced by sharp resistance spikes. At high magnetic field, the large g*m* leads to full spin polarization, where we found sudden increase in resistance around the filling factors of half-integer, accompanied by complete disappearance of fractional quantum Hall (QH) states. Along with its large effective mass and the high electron mobility, our result indicates that the ZnO 2D system is ideal for investigating the effect of electron correlations in the QH regime.