Theory of Magnetotransport in the Dirac and Weyl Semimetals

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" Theory of Magnetotransport in the Dirac and Weyl Semimetals "
Imran, Muhammad Hershfield, Selman

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1108810
Doc. No	:	TLpq2468393989
Main Entry	:	Hershfield, Selman
	:	Imran, Muhammad
Title & Author	:	Theory of Magnetotransport in the Dirac and Weyl Semimetals\ Imran, MuhammadHershfield, Selman
College	:	University of Florida
Date	:	2020
student score	:	2020
Degree	:	Ph.D.
Page No	:	98
Abstract	:	The electron transport is a very active area of research in physics. In this thesis we study the magnetotransport of the Dirac and Weyl semimetals, theoretically. We find their dependence on external magnetic field. These materials are exotic, and exhibit unusual magnetic field dependence on their magnetotransport properties. The most prominent effect is the chiral anomaly effect. This is a Berry curvature effect. According to this effect the magneoconductivity increases in the direction of magnetic field. At first chiral anomaly was observed in Weyl semimetals, TaAs. Now there are plenty of materials that exhibit chiral anomaly characteristics. We study these semimetals magnetotransport properties both from the semiclassical and quantum perspective. For the semicalssical theory, we develop an equation of motion theory for the Dirac and Weyl semimetals by using the Wigners method. Later we solve the distribution function to calculate formulas of magnetotransport. We limit ourself to the linear response of the electric field. The derived formulas are matched with the experimental results. This includes the chiral anomaly effect. For the quantum theory, we use the Kubo formalism. This is a linear response theory. We derive the magnetotransport properties in a strong magnetic field. The formulas of magnetotransport show quantization effect. This is consistent with the Shubnikov De has oscillations in the magneto transport properties. The low energy Dirac and Weyl semimetals are allowed to have asymmetric energy dispersion. This is interesting that this asymmetry in energy dispersion allows a type of Hall effect, Planar Hall effect. We derive the formula of the Planar Hall effect. The oscillations in the Planar Hall effect can become a fingerprint to detect the anomalous transport in the Dirac and Weyl semimetals. The Planar Hall effect is also observed in the Dirac and Weyl semimetals, experimentally.
Subject	:	Condensed matter physics
	:	Materials science
	:	Physics
	:	Topology