Abstract
Electron spin resonance reveals the spin behavior of conduction () and localized () electrons in (, Ga). Both the and compounds exhibit a metal-insulator transition at 113 K with the simultaneous formation of a spin-singlet ground state in the electron system of the donor molecules. The behavior is consistent with charge ordering in at the metal-insulator transition. At 5 K, the compound orders antiferromagnetically, even though the electrons, which normally would facilitate magnetic exchange, are localized nonmagnetic singlets.
- Received 28 August 2007
DOI:https://doi.org/10.1103/PhysRevLett.100.147602
©2008 American Physical Society