Figure 1

(Color online) BLG continuum-model band structure. Depending on the doping level, the 2DES can have either one or two conduction-band Fermi surfaces.Reuse & Permissions

Figure 2

(Color online) BLG static response in units of the Fermi-level density of states of band 3, $\nu =\left({\epsilon }_{\text{F}}+t_{\perp }/2\right)/\left(2\pi v^2\right)$, as a function of $q/k_{\text{F}3}$. (a) ${\chi }_{\rho \rho }^{\left(0\right)}\left(q,0\right)$. The (black) dashed line is the result obtained within the two-band model (Ref. 12), while the (red) solid line is the result obtained within the four-band model for doping level $n={10}^{12}{\text{cm}}^{-2}$, corresponding to the (red) solid line in Fig. 1. The (blue) dash-dotted line gives the static response for $n=5\times {10}^{13}{\text{cm}}^{-2}$ corresponding to the (blue) dash-dotted line in Fig. 1. Inset: small momenta region of the heavily doped result. From left to right, the vertical dashed lines are at $2k_{\text{F}1}$, $k_{\text{F}1}+k_{\text{F}3}$, and $2k_{\text{F}3}$. (b) ${\chi }_{{\rm Y}{\rm Y}}^{\left(0\right)}\left(q,0\right)$ with the same labeling as in panel (a). The two-band model ${\chi }_{{\rm Y}{\rm Y}}^{\left(0\right)}\left(q,0\right)$ reported here has been calculated with a cutoff $k_{\text{c}}=t_{\perp }/v$.Reuse & Permissions

Figure 3

(Color) BLG RPA dynamical dielectric functions for low-doping $n={10}^{12}{\text{cm}}^{-2}$ and ${\alpha }_{\text{ee}}=0.5$. The left panel shows $\mathfrak{I}m\left[1/{\epsilon }_{\rho \rho }\left(q,\omega \right)\right]$ as a function of $q$ (in units of $k_{\text{F}3}$) and $\omega$ (in units of ${\epsilon }_{\text{F}}$). The right panel shows $\mathfrak{I}m\left[1/{\epsilon }_{{\rm Y}{\rm Y}}\left(q,\omega \right)\right]$.Reuse & Permissions

Figure 4

(Color) High density $\left(n=5\times {10}^{13}{\text{cm}}^{-2}\right)$ BLG RPA dynamical dielectric functions for the same model parameters as in Fig. 3. The inset in the right panel highlights the intersubband plasmon.Reuse & Permissions