Quantum dots with single-atom precision
Quantum dots with single-atom precision
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DOI：
10.1038/nnano.2014.129
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发表时间：
2014-07-01
影响因子：
38.3
通讯作者：
Erwin, Steven C.
中科院分区：
文献类型：
--
作者：
Foelsch, Stefan;Martinez-Blanco, Jesus;Erwin, Steven C.
量子点通常被称为人造原子，因为像真正的原子一样，它们将电子限制在具有离散能量的量子化状态。然而，尽管真正的原子是相同的，但大多数量子点由数百或数千个原子组成，大小和形状不可避免地会发生变化，因此，它们的波函数和能量也不可避免地会发生变化。静电门可以通过调整电子能级来缓解这些变化(1-3)，但更雄心勃勃的目标-通过消除量子点大小、形状和排列的统计变化来创造具有内在数字保真度的量子点-仍然难以实现(4-9)。我们使用扫描隧道显微镜来创建大小相同、确定的量子点。通过利用重构的半导体表面的晶格来固定每个原子的位置，我们有效地零误差地控制了点的形状和位置。这使得我们能够构建量子点分子，其耦合没有内在变化，但仍然可以在很大范围内以任意精度进行调节。数字保真度为没有固有展宽的量子点结构打开了大门--这是从纳米光子学(10)到量子信息处理(11，12)以及受限电子基础研究(13-17)等技术的一个重要目标。
Quantum dots are often called artificial atoms because, like real atoms, they confine electrons to quantized states with discrete energies. However, although real atoms are identical, most quantum dots comprise hundreds or thousands of atoms, with inevitable variations in size and shape and, consequently, unavoidable variability in their wavefunctions and energies. Electrostatic gates can be used to mitigate these variations by adjusting the electron energy levels(1-3), but the more ambitious goal of creating quantum dots with intrinsically digital fidelity by eliminating statistical variations in their size, shape and arrangement remains elusive(4-9). We used a scanning tunnelling microscope to create quantum dots with identical, deterministic sizes. By using the lattice of a reconstructed semiconductor surface to fix the position of each atom, we controlled the shape and location of the dots with effectively zero error. This allowed us to construct quantum dot molecules whose coupling has no intrinsic variation but could nonetheless be tuned with arbitrary precision over a wide range. Digital fidelity opens the door to quantum dot architectures free of intrinsic broadening-an important goal for technologies from nanophotonics(10) to quantum information processing(11,12) as well as for fundamental studies of confined electrons(13-17).