@article {1466, title = {Geometric-Phase-Effect Tunnel-Splitting Oscillations in Single-Molecule Magnets with Fourth-Order Anisotropy Induced by Orthorhombic Distortion }, journal = {EPL (Europhysics Letters)}, volume = {86}, year = {2009}, month = {2009/04/30}, pages = {27002}, abstract = { We analyze the interference between tunneling paths that occurs for a spin system with both fourth-order and second-order transverse anisotropy. Using an instanton approach, we find that as the strength of the second-order transverse anisotropy is increased, the tunnel splitting is modulated, with zeros occurring periodically. This effect results from the interference of four tunneling paths connecting easy-axis spin orientations and occurs in the absence of any magnetic field. }, doi = {10.1209/0295-5075/86/27002}, url = {http://arxiv.org/abs/0809.2289v2}, author = {Michael Foss-Feig and Jonathan R. Friedman} }