Critical state in a low-dimensional metal induced by strong magnetic fields

Article

关键词: DENSITY-WAVE STATE;    ORGANIC CONDUCTOR ALPHA-(BEDT-TTF)(2)KHG(SCN)(4);    CHIRAL SURFACE-STATES;    QUANTUM HALL REGIME;    FERMI-SURFACE;    UNIAXIAL-STRESS;    SUPERCONDUCTIVITY;    OSCILLATIONS;    ALPHA-(BEDT-TTF)(2)MHG(SCN)(4);    PHASE;   

DOI  :  10.1103/PhysRevB.62.14212

来源: SCIE

【 摘 要 】

We present the results of magnetotransport and magnetic torque measurements on the alpha-(BEDT-TTF)(2)KHg(SCN)(4) charge-transfer salt within its high-magnetic-field phase, in magnetic fields extending to 33 T and temperatures as low as 27 mK. While the experimentally determined phase diagram closely resembles that predicted by theoretical models for charge-density waves in strong magnetic fields, the phase that occurs at fields above similar to 23 T, which is expected to be either a modulated charge-density wave phase or a charge/spin-density wave hybrid, exhibits unusual physical properties that are most atypical of a density wave ground state. Notably, the resistivity undergoes a dramatic drop below similar to3 K within this phase, falling in an approximately exponential fashion at low temperatures, while the magnetic torque undergoes extensive hysteresis. This hysteresis, which occurs over a broad range of fields and gives rise to a large negative differential susceptibility partial derivativeM/partial derivativeB on reversing the direction of sweep of the magnetic field, is strongly temperature dependent and also has several of the physical characteristics predicted by critical-state models normally used to describe the pinning of vortices in type II superconductors. Such a behavior appears therefore only to be explained consistently in terms of persistent currents within the high-magnetic-field phase of alpha-(BEDT-TTF)(2)KHg(SCN)(4), although the origin of these currents remains an open question.

【 授权许可】

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