Emergence of Interlayer Coherence in Twist-Controlled Graphene Double Layers

We report enhanced interlayer tunneling with reduced linewidth at zero interlayer bias in a twist-controlled double monolayer graphene heterostructure in the quantum Hall regime, when the top (${\nu }_{\mathrm{T}}$) and bottom (${\nu }_{\mathrm{B}}$) layer filling factors are near ${\nu }_{\mathrm{T}}=\pm 1\mathrm{/}2,\pm 3\mathrm{/}2$ and ${\nu }_{\mathrm{B}}=\pm 1\mathrm{/}2,\pm 3\mathrm{/}2$, and the total filling factor $\nu =\pm 1$ or $\pm 3$. The zero-bias interlayer conductance peaks are stable against variations of layer filling factor, and signal the emergence of interlayer phase coherence. Our results highlight twist control as a key attribute in revealing interlayer coherence using tunneling.