  In this paper, based on the classic Chua's circuit, a charge-controlled
memristor is introduced to design a novel four-dimensional chaotic system. The
complex dynamics of the novel chaotic system such as equilibrium points,
stability, dissipation, bifurcation diagrams, Lyapunov exponent spectra and
phase portraits are investigated. By varying the initial conditions of the
system, it is found from numerical simulations that the system shows some
dynamics of great interests including double-wings chaotic attractors,
coexisting periodic-chaotic bubbles, asymmetric and symmetric coexisting
attrators. The results show that the novel circuit system has extreme
multistablity.
