University of Connecticut

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Condensed Matter Physics Seminar

Tuesday, October 4, 2016
2:00pm – 3:00pm

Storrs Campus
Gant Science Complex, Physics, Room PB-121

Jason T. Haraldsen, Assistant Professor, Department of Physics, University of North Florida

Understanding the Effects of Magnetism in Graphene: Working Towards Graphene-Based Spintronic Devices

Two-dimensional (2D) materials have gained an enormous amount of attention due to the possibility of merging charge and magnetism into a new technological evolution called spintronics. The most widely known and examined 2D material is graphene. However, most studies have only focused its capabilities for electronics. In this study, the use of magnetically substituted graphene nanoribbons is considered as a possible realization of a spintronic device. Using density functional theory, a simulated voltage is applied across the graphene nanoribbon (GNR), where a chromium dimer has been substituted into the lattice to induce magnetism within the carbon atoms. Using a first principles approach, the electronic and magnetic properties as a function of onsite potential, applied voltage, and magnetic configuration are determined, and through a calculation of the total energy for each magnetic configuration, an antiferromagnetic to ferromagnetic transition is produced. Through a mapping of this transition point to the calculated conductance for the system, a distinct change in electronic conductance throughout the graphene nanoribbon is revealed, which indicates the possibility of an electronic spin switch. Furthermore, it is also shown that this transition corresponds to a distinct change in the induced magnetization within the graphene nanoribbon. Therefore, this study shows the distinct possibility that electronic states in graphene can manipulated with an applied voltage to produce a spin flip in substituted magnetic atoms, which demonstrates the possibility of using graphene as a spintronic device.

Contact:

Dawn Rawlinson, 486-4916, dawn.rawlinson

Physics Department (primary)

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