Two novel phases of germa-graphene: Prediction, electronic and transport applications

In search of potential candidates for thermoelectric energy conversion, graphene and its derivatives always enthralled researchers for their exotic characteristics. Experimental feasibility of germanium (Ge) embedded graphene system (Tripathi et al., ACS Nano 12 (2018) 4641–4647) motivates us to explore prediction and applications of two new phases of germa-graphene structures by employing first-principles calculations in combination with machine-learning approaches. Formal stability analysis reveal that these phases are stable as well as feasible for experimental fabrications. Depending upon Ge concentration, germa-graphene exhibits semi-metallic Dirac cone as well as parabolic dispersions. Further doping-dependent variations in electrical conductivity and Seebeck response enables their applications by securing suitable thermoelectric figure of merit. It is interesting to explore width-dependent rectifying applications of germa-graphene nanoribbons.