Anomalous Hall effect and magnetotransport effects in the organic superconductor (TMTSF ) 2 CIO 4

1985 ◽  
Vol 314 (1528) ◽  
pp. 97-103
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Magnetic State ◽  
Quantum Hall ◽  
Anomalous Hall Effect ◽  
Organic Superconductor ◽  
Hall Resistance ◽  
Threshold Field ◽  
Organic Conductor ◽  
Lower Temperature

The organic conductor (TMTSF) 2 CIO 4 exhibits unusual magnetotransport effects below 30 K. The resistivity and thermopower have large, anisotropic changes in a magnetic field, whereas the thermal conductivity is hardly affected. At lower temperature ( T ≤ 5 K) a magnetic field applied along the c * direction causes a phase transition from a metallic, non-magnetic state to a semimetallic, magnetic state. This orbitally induced transition appears to be unique in nature. Above the threshold field for this transition steps in the Hall resistance are observed, suggestive of the quantum Hall effect. In this paper we review the magnetotransport experiment in these materials and discuss the possible origins of the unusual phenomena observed.

scholarly journals HALL EFFECT STUDIES OF THE SUPERCONDUCTING FERROMAGNET UCoGe

2017 ◽  
Vol 35 (2) ◽  
Author(s):  
Danica Krstovska ◽  
Eden Steven ◽  
Andhika Kiswandhi ◽  
James S. Brooks
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Anomalous Hall Effect ◽  
Simple Relation ◽  
Hall Resistance ◽  
Unusual Behavior ◽  
Perpendicular Component ◽  
Induced Changes ◽  
The Magnetic Field ◽  
Characteristic Field

We find that the Hall effect in a single crystal of UCoGe varies as a function of the angle  between the applied magnetic field and the easy magnetic axis up to fields of 18 T at 0.2 K, i.e. in the region where both superconductivity and ferromagnetic order coexist. Instead of following the conventional cos dependence the two components that com-prise the total Hall resistance, the anomalous and ordinary Hall effect, exhibit quite an unusual behavior with the field direction. The anomalous Hall effect is found to be determined by the parallel component of the magnetization. We sug-gest that the field induced changes in magnetization due to the field rotation play an important role in the observed unu-sual behavior. The ordinary Hall effect cannot be described by the simple relation to the perpendicular component of the magnetic field implying that this component of the Hall effect may be also affected by the variations in magnetization at the characteristic field (kink field). A field induced moment polarization is also observed in Hall effect as in magnetore-sistance, which advances previous findings in UCoGe. The Hall effect slope reverses sign at the kink field indicative of small but possible Fermi surface reconstruction around this field. Our findings show that in UCoGe multiple mecha-nisms contribute to the observed field induced moment polarization at the kink field.

scholarly journals Quantum anomalous Hall effect

2013 ◽  
Vol 1 (1) ◽  
pp. 38-48 ◽  
Author(s):  
Ke He ◽  
Yayu Wang ◽  
Qi-Kun Xue
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Condensed Matter ◽  
Semiconductor Industry ◽  
Quantum Hall ◽  
Special Kind ◽  
Anomalous Hall Effect ◽  
Electronic Systems ◽  
Quantum Anomalous Hall Effect

Abstract Hall effect is a well-known electromagnetic phenomenon that has been widely applied in the semiconductor industry. The quantum Hall effect discovered in two-dimensional electronic systems under a strong magnetic field provided new insights into condensed matter physics, especially the topological aspect of electronic states. The quantum anomalous Hall effect is a special kind of the quantum Hall effect that occurs without a magnetic field. It has long been sought after because its realization will significantly facilitate the studies and applications of the quantum Hall physics. In this paper, we review how the idea of the quantum anomalous Hall effect was developed and how the effect was finally experimentally realized in thin films of a magnetically doped topological insulator.

Possible quantum Hall effect in a magnetic-field-induced phase transition in the quasi-one-dimensional CDW organic conductor, HMTSF–TCNQ

2015 ◽  
Vol 460 ◽  
pp. 241-244 ◽  
Author(s):  
Keizo Murata ◽  
Yuhei Fukumoto ◽  
Keiichi Yokogawa ◽  
Woun Kang ◽  
Ryo Takaoka ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Organic Conductor ◽  
One Dimensional

scholarly journals Magnetic-Field-Induced Phase Transition and a Possible Quantum Hall Effect in the Quasi-One-Dimensional CDW Organic Conductor HMTSF-TCNQ

2014 ◽  
Vol 05 (08) ◽  
pp. 673-679 ◽  
Author(s):  
Keizo Murata ◽  
Yuhei Fukumoto ◽  
Keiichi Yokogawa ◽  
Woun Kang ◽  
Ryo Takaoka ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Quantum Hall ◽  
Organic Conductor ◽  
One Dimensional

scholarly journals The quantum Hall effect in the absence of disorder

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Kyung-Su Kim ◽  
Steven A. Kivelson
Keyword(s):  
Magnetic Field ◽  
Hall Effect ◽  
Quantum Hall Effect ◽  
Finite Interval ◽  
Quantum Hall ◽  
Wigner Crystal ◽  
Quasi Particle ◽  
Hall Conductance ◽  
Finite Extent

AbstractIt is widely held that disorder is essential to the existence of a finite interval of magnetic field in which the Hall conductance is quantized, i.e., for the existence of “plateaus” in the quantum Hall effect. Here, we show that the existence of a quasi-particle Wigner crystal (QPWC) results in the persistence of plateaus of finite extent even in the limit of vanishing disorder. Several experimentally detectable features that characterize the behavior in the zero disorder limit are also explored.

INFLUENCE OF NEARBY QD LAYER ON 2DES IN QUANTUM HALL REGIME

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1445-1449
Author(s):  
K. TAKEHANA ◽  
Y. IMANAKA ◽  
T. TAKAMASU ◽  
M. HENINI
Keyword(s):  
Magnetic Field ◽  
Transport Properties ◽  
Gate Voltage ◽  
Quantum Hall ◽  
Electron System ◽  
Hall Resistance ◽  
Field Range ◽  
Voltage Range ◽  
Quantum Hall Regime ◽  
Hall Regime

We have investigated transport properties in high magnetic field of a gated two-dimensional electron system (2DES) separated by a thin barrier from a layer of self-assembled InAs quantum dots (QDs) in the quantum Hall regime. The quality of 2DES was found to be high enough to observe both integer and fractional quantum Hall effect (QHE), despite the proximity of the QD layer to the 2DES. However, significant suppression of the magnetoresistance (ρ xx ) and Hall resistance (ρ xy ) were observed in higher magnetic field range of filling factor ν < 1 when a positive voltage was applied to the front gate. The gate voltage dependence of ρ xx and ρ xy shows a well-defined hysteresis loop at the narrow gate voltage range between -0.2 and +0.2 V at ν < 1, while no anomaly was observed at ν > 1. We deduce that charging and discharging of QDs occurs when the gate voltage is varied around Vg ~ 0 V, which indicates that the electron charge states of the QDs affect the transport properties of the nearby 2DES only at ν < 1. We infer that the spin-flip process induces a non-equilibrium state in the 2DEG, which causes the suppression of ρ xx and ρ xy .

Sign in / Sign up

Export Citation Format

Share Document