Seo M, Choi H K, Lee S-Y, Kim N, Chung Y, Sim H-S, Umansky V, Mahalu D
Department of Physics, Pusan National University, Busan 609-735, Republic of Korea.
Braun Center for Submicron Research, Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Phys Rev Lett. 2013 Jan 25;110(4):046803. doi: 10.1103/PhysRevLett.110.046803. Epub 2013 Jan 24.
We experimentally investigate the charge (isospin) frustration induced by a geometrical symmetry in a triangular triple quantum dot. We observe the ground-state charge configurations of sixfold degeneracy, the manifestation of the frustration. The frustration results in omnidirectional charge transport, and it is accompanied by nearby nontrivial triple degenerate states in the charge stability diagram. The findings agree with a capacitive interaction model. We also observe unusual transport by the frustration, which might be related to elastic cotunneling and the interference of trajectories through the dot. This work demonstrates a unique way of studying geometrical frustration in a controllable way.
我们通过实验研究了三角形三量子点中几何对称性所引起的电荷（同位旋）简并。我们观察到了六重简并的基态电荷构型，这是简并的表现。这种简并导致了全方位的电荷传输，并且在电荷稳定性图中伴随着附近的非平凡三重简并态。这些发现与电容相互作用模型相符。我们还观察到了由简并引起的异常传输，这可能与弹性共隧穿以及通过量子点的轨迹干涉有关。这项工作展示了一种以可控方式研究几何简并的独特方法。
