Division of Solid State Physics and NanoLund, Lund University, Box 118, S-221 00 Lund, Sweden.
Center for Analysis and Synthesis, Lund University, Box 124, S-221 00 Lund, Sweden.
Phys Rev Lett. 2018 Oct 12;121(15):156802. doi: 10.1103/PhysRevLett.121.156802.
We study spin transport in the one- and two-electron regimes of parallel-coupled double quantum dots (DQDs). The DQDs are formed in InAs nanowires by a combination of crystal-phase engineering and electrostatic gating, with an interdot tunnel coupling (t) tunable by one order of magnitude. Large single-particle energy separations (up to 10 meV) and |g^{*}| factors (∼10) enable detailed studies of the B-field-induced transition from a singlet-to-triplet ground state as a function of t. In particular, we investigate how the magnitude of the spin-orbit-induced singlet-triplet anticrossing depends on t. For cases of strong coupling, we find values of 230 μeV for the anticrossing using excited-state spectroscopy. Experimental results are reproduced by calculations based on rate equations and a DQD model including a single orbital in each dot.
我们研究了平行耦合双量子点（DQD）中一个和两个电子态的自旋输运。通过晶体相工程和静电门控的组合，在 InAs 纳米线中形成 DQD，两个点之间的隧道耦合（t）可以调节一个数量级。大的单粒子能分离（高达 10 meV）和 |g*| 因子（约 10）使我们能够详细研究 B 场诱导的从单重态到三重态基态的跃迁，作为 t 的函数。特别是，我们研究了自旋轨道诱导的单重态三重态交叉的大小如何取决于 t。对于强耦合的情况，我们使用激发态光谱法在 230 μeV 处找到了交叉的数值。实验结果通过基于速率方程和包括每个点中的单个轨道的 DQD 模型的计算得到了重现。
