Probing the singlet-triplet splitting in double quantum dots: Implications of the ac field amplitude
Probing the singlet-triplet splitting in double quantum dots: Implications of the ac field amplitude
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DOI：
10.1103/physrevb.100.195421
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发表时间：
2019-11
影响因子：
3.7
通讯作者：
G. Giavaras;Y. Tokura
中科院分区：
文献类型：
--
作者：
G. Giavaras;Y. Tokura
我们考虑一个能量失谐量受交流电场控制的双量子点。我们证明了一种能量配置，其中交流感应电流流过双点直接探测小交流场振幅的自旋轨道反交叉点。相反，随着交流振幅的增加，形成了电流反共振，失去了关于自旋轨道相互作用的直接信息。这一结果表明，大的交流振幅并不一定有利于自旋轨道耦合双自旋态的光谱。此外，我们研究了交流感应电流峰值与交流振幅的关系，并表明当交流场形成自旋阻塞态时，电流会受到抑制。这种效应产生了电流的特征模式，可以通过调节交流幅度来随意控制。我们的结果可以通过在自旋封锁制度下进行电子输运测量来探索。
We consider a double quantum dot whose energy detuning is controlled by an ac electric field. We demonstrate an energy configuration for which the ac-induced current flowing through the double dot directly probes the spin-orbit anticrossing point for small ac field amplitudes. On the contrary, as the ac amplitude increases a current antiresonance is formed, and the direct information about the spin-orbit interaction is lost. This result indicates that a large ac amplitude is not necessarily advantageous for the spectroscopy of spin-orbit coupled two-spin states. Moreover, we investigate the ac-induced current peaks versus the ac amplitude and show a current suppression when the ac field forms spin blocked states. This effect gives rise to a characteristic pattern for the current which can be controlled at will by tuning the ac amplitude. Our results can be explored by performing electronic transport measurements in the spin blockade regime.