Figure a-c shows representative snapshots taken from AIMD simulations at 3.0, 6.0 and 11.1 MPM, covering the EMT concentration range. Complete trajectories obtained from AIMD were then used to calculate the averaged densities of states (DoS) using the G 0 W 0 method (for details see SI) as presented in Figure e,g,i. We see a progressive narrowing and filling of the gap between the highest occupied and lowest unoccupied orbitals as the concentration of the alkali metal increases with rising density at the Fermi level as a signature of the gradual EMT.