Transport property of an organic conductor alpha-(BEDT-TTF)(2)I-3 under high pressure - Discovery of a novel type of conductor

Tajima, N Tamura, M Nishio, Y Kajita, K Iye, Y

N. Tajima et al., Transport property of an organic conductor alpha-(BEDT-TTF)(2)I-3 under high pressure - Discovery of a novel type of conductor, J PHYS JPN, 69(2), 2000, pp. 543-551

16

INGLESE

Article

Physics

JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN

0031-9015 → ACNP

69

2

2000

543 - 551

ISI

0031-9015(200002)69:2<543:TPOAOC>2.0.ZU;2-8

We have found quite a new type of transport phenomenon in an organic crysta l alpha-(BEDT-TTF)(2)I-3 under high pressure. Essentially, it is a semimeta l or a narrow gap semiconductor. But, the transport property is peculiar. T he conductivity of this the carrier (hole) density and mobility change by a about 6 orders of magnitude. They change in a manner so that the effects j ust cancel out giving rise to the temperature independent conductivity. At low temperatures, the system is in a state with high mobility (3 x 10(5) cm (2)/V.sec) and low carrier density (5 x 10(15) cm(-3)). This state has been found to be very sensitive to magnetic field. We propose a mechanism for t he extremely strong temperature dependence of the carrier density. It is ba sed on the band structure and takes the thermal effect into consideration.