and 1.5 respectively) indicated by the horizontal dotted liens in panel (a). The two dotted circles in panels (b) and (c) are indicative of the Fermi circles for $\pm +(\vec{k}\times\vec{\sigma})\cdot\hat{z}$ Dirac cones which provide rough indications of the in-plane spin accumulation directions at the $k$ space points on the EECs. []{data-label="gbigLambdaComb1"}](bigLambdaComb1.eps)

Fig. \[gbigLambdaComb1\] shows the dispersion relations and the EECs as $\lambda$ increases further relative to $|\vec{M}|$. As $\lambda$ is increased from 0, the energy of the lowest energy particle band at $\vec{k}=0$ is pushed downwards and that of the highest energy hole band pushed upwards until the two bands touch each other when $\lambda = |\vec{M}|$. At this point ($\lambda=0.5$ in panel (a)) we no longer have two the well-resolved Dirac cones with two separate Dirac points in $\lambda = 0.2$ in panel (a) of the figure. A further increase in $\lambda$ leads to a bandgap opening up between the particle and hole bands. Panels (b) and (c) of the figure show the EECs at two values of energy for $\lambda > |\vec{M}|$. The in-plane spin accumulations at various $k$ space points can still be roughly understood as the spin accumulations of two overlapping circular cross sections of perfect 