Strain-tuning of transport gaps and semiconductor-to-conductor phase transition in twinned graphene

We show, through the use of Landauer-Büttiker (LB) formalism and a tight-binding (TB) model, that transport gap twinned graphene can be tuned application uniaxial strain in direction normal to twin band. Remarkably, we find Egap bears square-root dependence on control parameter ϵx−ϵc, where ϵx is applied ϵc∼19% critical strain. interpret this as evidence criticality underlying continuous phase transition, with ϵx−ϵc playing role order parameter. For ϵx<ϵc, non-zero material semiconductor, whereas for ϵx>ϵc closes zero becomes conductor, which evinces semiconductor-to-conductor transition. The computed exponent 1/2 places transition meanfield universality class, enables far-reaching analogies other systems same class.