Abstract
We report a unique temperature-induced insulator-metal transition in that is accompanied by a simultaneous magnetostructural change from a nonmagnetic monoclinic phase to a magnetic orthorhombic phase. Such a concurring magnetostructural and insulator-metal transformation is a manifestation of a strong competition between Peierls and Stoner mechanisms that governs a crossover from an electron-pairing to an electron-localization scenario in this system. Therefore, the phase stability of is controlled by a subtle interplay among the Peierls mechanism, Stoner mechanism, and phonon free energy. Our findings not only resolve the longstanding magnetostructural puzzle of but also provide a realistic system for the Peierls-Hubbard model.
- Received 16 July 2014
DOI:https://doi.org/10.1103/PhysRevLett.113.176401
© 2014 American Physical Society