J. Phys. IV France
Volume 114, April 2004
Page(s) 343 - 345

J. Phys. IV France
114 (2004) 343
DOI: 10.1051/jp4:2004114078

Possible quantum hall effect in the two-dimensional organic conductor, ${\tau }$-(EDO-S, S-DMEDT-TTF) 2(AuBr 2) 1+y in the two-Fermi surface system

K. Murata1, T. Nakanishi1, H. Yoshino1, T. Konoike1, J. Brooks1, D. Graf2 and G.C. Papavassiliou3

1  Graduate School of Science, Osaka City University, Sumiyoshi-ku, Osaka 558-8585, Japan
2  Dept. of Phys. Florida St. Univ./ Nat'l High Mag. Field Lab., Tallahassee, FL 32306-4005, USA
3  Theor. and Phys. Chem. Inst., National Hellenic Research Foundation, Athens, 116/8577, Greece

In the two-dimensional organic conductor, ${\tau }$ -(EDO- S, S-DMEDT-TTF) 2(AuBr 2)1+y, we have observed Shubnikov de Hass oscillations with Landau level down to n = 1 (quantum limit), and found Hall resistance plateau above 35 Tesla.( n = 1). This plateau might be interpreted as a new quantum Hall effect (QHE), realized by two 2D Fermi surfaces (FS). Since the areas and effective masses are, 0.66%(1.6 m0) and 6.1%(3.5-5.2 m0) of the first Brillouin zone, the large FS can play the role of electron reservoir for the small FS. This explains the plateau structure in Hall effect. To confirm that two series of oscillations are associated with really thermodynamic phenomena, we performed torque and Shubnikov de Haas studies. Key words. Two-dimensional organic conductor, quantum Hall effect.

© EDP Sciences 2004