Details

Autor(en) / Beteiligte

• Peterseim, T
• Ivek, T
• Schweitzer, D
• Dressel, M

Titel

Electrically induced phase transition in [alpha]-(BEDT-TTF) sub(2) I sub(3): Indications for Dirac-like hot charge carriers

Ist Teil von

• Physical review. B, 2016-06, Vol.93 (24)

Erscheinungsjahr

2016

Quelle

APS

Beschreibungen/Notizen

• The two-dimensional organic conductor [alpha]-(BEDT-TTF) sub(2) I sub(3) undergoes a metal-insulator transition at T sub(CO)= 135 K due to electronic charge ordering. We have conducted time-resolved investigations of its electronic properties in order to explore the field- and temperature-dependent dynamics. At a certain threshold field, the system switches from a low-conducting to a high-conducting state, accompanied by a negative differential resistance. Our time-dependent infrared investigations indicate that close to T sub(CO), the strong electric field pushes the crystal into a metallic state with optical properties similar to the one for T> T sub(CO). Well into the insulating state, however, at T= 80K, the spectral response evidences a completely different electronically induced high-conducting state. Applying a two-state model of hot electrons explains the observations by excitation of charge carriers with a high mobility. They resemble the Dirac-like charge carriers with a linear dispersion of the electronic bands found in [alpha]-(BEDT-TTF) sub(2) I sub(3) at high pressure. Extensive numerical simulations quantitatively reproduce our experimental findings in all details.