Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
Phys Rev Lett. 2012 Nov 9;109(19):196601. doi: 10.1103/PhysRevLett.109.196601. Epub 2012 Nov 7.
In graphene, the valleys represent spinlike quantities and can act as a physical resource in valley-based electronics to produce novel quantum computation schemes. Here we demonstrate a direct route to tune and read the valley quantum states of disordered graphene by measuring the mesoscopic conductance fluctuations. We show that the conductance fluctuations in graphene at low temperatures are reduced by a factor of 4 when valley triplet states are gapped in the presence of short-range potential scatterers at high carrier densities. We also show that this implies a gate tunable universal symmetry class that outlines a fundamental feature arising from graphene's unique crystal structure.
在石墨烯中，谷代表类似自旋的量，并可以作为谷基电子学中的物理资源，用于产生新的量子计算方案。在这里，我们通过测量介观电导波动，展示了一种直接调控和读取无序石墨烯谷量子态的方法。我们表明，在高温下存在短程势散射体时，谷三重态被能隙隔开，低温下石墨烯的电导波动会减小 4 倍。我们还表明，这意味着一个门可调谐的通用对称类，它概述了源自石墨烯独特晶体结构的基本特征。
