Abstract
Using far-infrared spectroscopy in magnetic fields up to 12 T we have studied a two-dimensional dimer spin gap system We found several infrared-active modes in the dimerized state (below 10 K) in the frequency range from 3 to The measured splitting from the ground state to the excited triplet sublevel is and the other two triplet state sublevels in zero magnetic field are below and above the sublevel. Another multiplet is at from the ground state. A strong electric dipole active transition polarized in the plane is activated in the dimer spin system below 15 K at
- Received 13 September 1999
DOI:https://doi.org/10.1103/PhysRevB.61.14342
©2000 American Physical Society