Consider a well 5 nm wide and 0.3 eV deep in GaAs. The lowest state in this well has a binding energy of 0.210 eV so κ = 0.61 nm-1 outside the well. Estimate the splitting when two such wells are separated by a 5 nm barrier (taking the effective mass as 0.067 everywhere). Do not aim for great accuracy but make drastic approximations to get a simple expression for t that will tell you the order of magnitude of the splitting.