Influence of nonequilibrium phonons on the spin dynamics of a single Cr atom
Influence of nonequilibrium phonons on the spin dynamics of a single Cr atom
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非平衡声子对单个 Cr 原子自旋动力学的影响
DOI：
10.1103/physrevb.101.035305
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发表时间：
2020
影响因子：
3.7
通讯作者：
Besombes L.
中科院分区：
文献类型：
--
作者：
Tiwari V.;Makita K.;Arino M.;Morita M.;Kuroda S.;Boukari H.;Besombes L.
我们分析了光学产生的非平衡声子对嵌入量子点中的单个Cr原子的自旋弛豫和有效自旋温度的影响。利用三脉冲抽运探测技术，我们发现在共振光抽运实验中测得的自旋弛豫强烈地依赖于光激发条件。我们观察到一个孤立的铬在黑暗中的加热时间短于几百纳秒后，初始的高功率非共振激发脉冲。冷却时间大于几十微秒，独立的激励，在相同的实验条件下获得。我们发现，一个可调的自旋-晶格耦合依赖于非平衡声子的密度可以解释所观察到的动力学。低能量的激发条件下，发现Cr的自旋状态can有效地填充由非共振光激发，制备和读出的共振光泵浦和保存在黑暗中几微秒。
We analyze the influence of optically generated nonequilibrium phonons on the spin relaxation and effective spin temperature of an individual Cr atom inserted in a quantum dot. Using a three-pulse pump-probe technique, we show that the spin relaxation measured in resonant optical pumping experiments strongly depends on the optical excitation conditions. We observe for an isolated Cr in the dark a heating time shorter than a few hundred nanoseconds after an initial high-power nonresonant excitation pulse. A cooling time larger than a few tens of microseconds, independent of the excitation, is obtained in the same experimental conditions. We show that a tunable spin-lattice coupling dependent on the density of nonequilibrium phonons can explain the observed dynamics. Low-energy excitation conditions are found where the Cr spin statescan be efficiently populated by a nonresonant optical excitation, prepared and read out by resonant optical pumping and conserved in the dark for a few microseconds.