Semiclassical study of single-molecule magnets and their quantum phase transitions

Abstract: We present a study of systems of single-molecule magnets using a semiclassical analysis and catastrophe theory. Separatrices in parameter space are constructed which are useful to determine the structure of the Hamiltonians energy levels. In particular the Maxwell set separatrix determines the behavior of the ground state of the system. We consider an external magnetic field with two components, one parallel to the easy magnetization axis of the molecule and the other perpendicular to it. Using the fidelity and heat capacity we were able to detect the signals of the QPTs as a function of the magnetic field components.