  Monolayer silicene is a front runner in the 2D-Xene family, which also
comprises germanene, stanene, and phosphorene, to name a few, due to its
compatibility with current silicon fabrication technology. Here, we investigate
the utility of 2D-Xenes for straintronics using the ab-initio density
functional theory coupled with quantum transport based on the Landauer
formalism. With a rigorous band structure analysis, we show the effect of
strain on the K-point, and calculate the directional piezoresistances for the
buckled Xenes as per their critical strain limit. Further, we compare the
relevant gauge factors, and their sinusoidal dependences on the transport angle
akin to silicene and graphene. The strain-insensitive transport angles
corresponding to the zero gauge factors are 81 degree and 34 degree for
armchair and zigzag strains, respectively, for silicene and germanene. For
stanene as the strain limit is extended to 10% and notable changes in the
fundamental parameters, the critical angle for stanene along armchair and
zigzag directions are 69 degree and 34 degree respectively. The small values of
gauge factors are attributed to their stable Dirac cones and strain-independent
valley degeneracies. We also explore conductance modulation, which is quantized
in nature and exhibits a similar pattern with other transport parameters
against a change in strain. Based on the obtained results, we propose the
buckled Xenes as an interconnect in flexible electronics and are promising
candidates for various applications in straintronics.
