Ultrafast switching to a stable hidden quantum state in an electronic crystal.
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.
Department of Complex Matter, Jozef Stefan Institute, Jamova 39, Ljubljana SI-1000, Slovenia.
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Stojchevska
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Vaskivskyi
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Mertelj
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Kusar
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Svetin
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Brazovskii
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Mihailovic