Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phase
Manipulating the magnetic state of a carbon nanotube Josephson junction using the superconducting phase
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DOI：
10.1103/physrevb.91.241401
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发表时间：
2015-06-09
影响因子：
3.7
通讯作者：
Deblock, R.
中科院分区：
文献类型：
--
作者：
Delagrange, R.;Luitz, D. J.;Deblock, R.
实验表明，超导导线上的量子点的磁状态是由量子点两端的超导相位差控制的。这是通过探测约瑟夫森电流和碳纳米管结的超导相位差之间的关系来完成的，碳纳米管结的近藤能量和超导能隙具有可比的大小。它表现出明显的非谐行为，揭示了相位介导的单重态到二重态的转变。我们得到了一个很好的定量协议与数值精确的量子蒙特卡罗计算。这提供了强有力的支持，我们确实观察到的相位控制的零温度水平交叉跃迁起源于强的本地电子关联的有限温度签名。
The magnetic state of a quantum dot attached to superconducting leads is experimentally shown to be controlled by the superconducting phase difference across the dot. This is done by probing the relation between the Josephson current and the superconducting phase difference of a carbon nanotube junction whose Kondo energy and superconducting gap are of comparable size. It exhibits distinctively anharmonic behavior, revealing a phase-mediated singlet-to-doublet transition. We obtain an excellent quantitative agreement with numerically exact quantum Monte Carlo calculations. This provides strong support that we indeed observed the finite-temperature signatures of the phase-controlled zero temperature level crossing transition originating from strong local electronic correlations.