Ground-State Cooling of a Carbon Nanomechanical Resonator by Spin-Polarized Current
Ground-State Cooling of a Carbon Nanomechanical Resonator by Spin-Polarized Current
复制标题
DOI：
10.1103/physrevlett.113.047201
复制
发表时间：
2014-07-21
影响因子：
8.6
通讯作者：
Rastelli, G.
中科院分区：
文献类型：
--
作者：
Stadler, P.;Belzig, W.;Rastelli, G.
研究了由悬浮的碳纳米管量子点与两个铁磁体接触实现的量子力学谐振器的非平衡稳态。由于自旋-轨道相互作用和/或外部磁场梯度，点上的自旋直接耦合到弯曲本征模。因此，纳米机械运动引起隧穿电子的非弹性自旋翻转。有限偏置电压下的自旋极化电流导致机械模式的加热或主动冷却。我们表明，最大的冷却是在共振输运时，两个点之间的能量分裂的相反的自旋等于振动频率。即使对于弱的电子谐振器耦合和中等的极化，我们也可以实现基态冷却，例如，T = 10 Ω的引线温度。
We study the nonequilibrium steady state of a mechanical resonator in the quantum regime realized by a suspended carbon nanotube quantum dot in contact with two ferromagnets. Because of the spin-orbit interaction and/or an external magnetic field gradient, the spin on the dot couples directly to the flexural eigenmodes. Accordingly, the nanomechanical motion induces inelastic spin flips of the tunneling electrons. A spin-polarized current at finite bias voltage causes either heating or active cooling of the mechanical modes. We show that maximal cooling is achieved at resonant transport when the energy splitting between two dot levels of opposite spin equals the vibrational frequency. Even for weak electron-resonator coupling and moderate polarizations we can achieve ground-state cooling with a temperature of the leads, for instance, of T = 10 omega.