The Anomalous Hall Effect in Ultra-Thin Amorphous CNi3 Films

ORAL

Abstract

The anomalous Hall resistance in homogeneous CNi$_3$ films with sheet resistance near the quantum resistance was studied. Tunneling measurements show that the saturation behavior is commensurate with the emergence of the 2D Coulomb gap, suggesting that e-e interactions mediate the high-disorder phase. The saturation of anomalous Hall resistance is associated with the crossover from the weak- localization regime to that of a 2D correlated insulator. In the weak-localization regime, where the sheet conductance G $\gg e^2/h$, the anomalous Hall resistance of the films increases with increasing disorder and the Hall conductance scales as G$_{xy} \propto G^\varphi$ with $\varphi$ = 1.6. However, at sufficiently high disorder the system begins to enter the 2D correlated insulator regime, at which point the Hall resistance R$_{xy}$ abruptly saturates and the scaling exponent becomes $\varphi$ = 2. The crossover is also clearly evident in the scaling behavior of the Hall conductivity as well as in the tunneling density of states.

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Authors

  • Yimin Xiong

    Department of Physics and Astronomy, Louisiana State University, Louisiana State University, Louisiana State University Department of Physics and Astronomy

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University

  • Philip Adams

    Department of Physics and Astronomy, Louisiana State University, ORNL, UT, ORNL/UT, UK, LSU, Louisiana State University, Zhejiang Normal University, Center for Computation and Technology, Louisiana State University, University of Tuebingen, Germany, Aristotle University of Thessaloniki, Greece, Max Planck Institute for Astrophysics, Max Plank Institute for Astrophysics, Laboratoire d'Astrophysique de Marseille, Albert Einstein Institute, California Institute of Technology, Dept. of Physics \& Astronomy, Louisiana State University, Baton Rouge, LA 70803, Dept. of Physics \& Astronomy, Louisiana State Univ., Baton Rouge, LA 70803, NASA Marshall Space Flight Center, Dept. of Physics \& Astronomy, Louisiana State University, Ohio State University, Wright State University, Department of Physics, North Carolina A\&T State University, Clark Atlanta University, Department of Electrical and Computer Engineering, Pennsylvania State University, University Park, P, Princeton University, University of New Orleans, Alabama A\&M University, Vanderbilt Univ., Konstanz Univ., Isik Univ., Department of Physics, Yale University