What’s The Magic Behind Graphene’s ‘Magic’ Angle?
For that angle, the models differ only slightly, because eliminating tunneling in the fully aligned regions doesn’t have a big impact: The TKV version of the story predicts 1.09 degrees for the magic angle versus 1.05 in MacDonald’s. MacDonald and Vishwanath peg the next-largest magic angle at 0.5 and less than 0.3 degrees, respectively; as experimenters refine their techniques, they’ll be able to pit the models against each other. What’s more, Vishwanath added, the stresses and distortions introduced by experimenters’ efforts to clamp graphene sheets together at particular angles tend to reduce the half-aligned area, a factor that the TKV model ignores.
Source: www.quantamagazine.org