Low Temperature Physics: 40, 371 (2014); https://doi.org/10.1063/1.4869591
Физика Низких Температур: Том 40, Выпуск 4 (Апрель 2014), c. 477-483    ( к оглавлению , назад )

Magnetic-field-induced phase transitions in the quasi-one-dimensional organic conductor HMTSF–TCNQ

K. Murata1, Y. Fukumoto1, K. Yokogawa1, R. Takaoka1, W. Kang2, J.S. Brooks3, D. Graf3, H. Yoshino1, T. Sasaki4, and R. Kato5

E-mail: muratak@sci.osaka-cu.ac.jp

1Graduate School of Science, Osaka City University, Osaka 558-8585, Japan

2Ewha Womans University, Seoul 120-750, Korea

3Nat’l. High Mag. Field Lab. Florida St. University, Tallahassee FL 32306-4005, USA

4Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan

5RIKEN, Wako, Saitama 351-0198

Received November 5, 2013


Motivated by an interest to see if the field-induced (FI) phase in the charge-density wave (CDW) system is similar to the field-induced-SDW (FISDW) in (TMTSF)2X, (TMTSF: tetramethyltetraselenafulvalene), we ex-amined the magnetic-field-induced phases in a quasi-one-dimensional (Q1D) organic conductor HMTSF–TCNQ (hexamethylene-tetraselenafulvalene-tetracyanoquinodimethane) under a pressure of 1.1 GPa, where the CDW occurring at 30 K is suppressed. The work was carried out by measurements of angular-dependent magnetoresistance oscillations and exploratory work on the Hall effect. It turned out that the FI-phase, most likely a FICDW for B > 0.1 T, accompany a quantum Hall effect, and the FI-phase transitions are controlled by the field component along the least conducting axis. Above 10 T, the lowest Landau level of the small 2D Fermi pocket (due to incomplete nesting of Fermi surface) exceeds the Fermi level, reaching the quantum limit. Although there are many differences between the CDW (HMTSF–TCNQ) and SDW ((TMTSF)2X) systems, a similar scenario for field-induced phases seems to hold.

PACS: 73.43.–f Quantum Hall effects;
PACS: 74.70.Kn Organic superconductors;
PACS: 71.45.Lr Charge-density-wave systems;
PACS: 75.30.Fv Spin-density waves.

Key words: HMTSF–TCNQ, charge-density wave, magnetoresistance, field-induced phase transitions, Fermi surface, nesting.