Ultrafast switching to a stable hidden quantum state in an electronic crystal.

Stojchevska, L; Vaskivskyi, I; Mertelj, T; Kusar, P; Svetin, D; Brazovskii, S; Mihailovic, D · Science · 2014

basic_science · Level V

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Abstract

Hidden states of matter may be created if a system out of equilibrium follows a trajectory to a state that is inaccessible or does not exist under normal equilibrium conditions. We found such a hidden (H) electronic state in a layered dichalcogenide crystal of 1T-TaS2 (the trigonal phase of tantalum disulfide) reached as a result of a quench caused by a single 35-femtosecond laser pulse. In comparison to other states of the system, the H state exhibits a large drop of electrical resistance, strongly modified single-particle and collective-mode spectra, and a marked change of optical reflectivity. The H state is stable until a laser pulse, electrical current, or thermal erase procedure is applied, causing it to revert to the thermodynamic ground state.