We have studied the angular dependence of magnetoresistance and Hall effect of the CDW organic conductor, HMTSF-TCNQ in order to see whether a magnetic-field-induced phase exists in the charge density wave (CDW) system, similarly to the magnetic-field-induced SDW phases in (TMTSF)2X. The anomaly in magnetoresistance was observed only around the pressure where the CDW is almost suppressed, i.e. around 0.8-1.1 GPa, but neither at low pressures (0 and 0.5 GPa) nor at high pressure above 2 GPa. This behavior is quite similar to that of (TMTSF)2X. At 1.1 GPa anomalies were found at fields of 0.2 T and 10 T. We speculate that at 1.1 GPa the field-induced phase is located between 0.2 T and 10 T, where 1D Fermi surface sheet and 2D Fermi-surface pocket are present. The Rxy shows plateau structure and Rxx was very small in the same region, suggestive of quantum Hall effect.
Bibliographical noteFunding Information:
This work is partially supported JSPS Inst. Prog. for Young Researcher Overseas Visits “Promoting International Young Researchers in Mathematics and Math. Sci. by OCAMI” and Grant-in-Aid Sci. Res. on Innovative Areas #23110722 from M. Education and NSF DMR#1005293 (FSU). W.K. was supported by a grant from the National Research Foundation of Korea (NRF), funded by the Korean Government ( MSIP ) (Nos. 2011-0030902 , 2010-00453 and 2008-0061893 ). Work at the NHMFL is supported by the NSF DMR#0654118 , and by the State of Florida . To achieve this experiment, the assistance of A. Kiswandhi, S. Benjamin, L. Winter of the Brooks group was indispensable. We appreciate Prof. H. Fujiwara of Osaka Prefecture University for the X-ray examination for selecting high quality crystals.
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- Charge density wave (CDW)