High Pressure Optical Absorption in Cs 2 TCNQ 3 Complexes Grown Under the Influence of Magnetic Field

Crystals of the organic semiconductor Cs 2 TCNQ 3 have been grown under the influence of magnetic field of 5 T and their optical properties have been compared with the crystals grown without magnetic field. The magnetic field effect manifests itself as the enhancement of the intradimer charge transfer band S 1 , which appears at around 1.3 eV in the E//a polarization. The high-pressure optical absorption measurements have shown that the S 1 band of the crystal grown at 5 T contains a new component, which is significantly intensified with increasing pressure up to 1 GPa, but diminishes as pressure increases further up to 4 GPa, and remains constant at higher pressures. This new component is additional to the component of S 1 band which has similar properties to that of the crystals grown without magnetic filed, which continuously grows up to 3 GPa and abruptly broadens out at higher pressures. The new component of S 1 is strongly linked to the ferromagnetism in this substance.