My current research interests in condensed matter physics include study of low dimensional materials. Today’s technology made it possible of creating artificial structures almost atom by atom and the discovery of new materials has opened a new area of research in the disciplines of materials science, physics, computational science, and engineering. We investigate carbon and boron nitride nanomaterials. Undergraduate and graduate students are involved in these research projects. Structural properties, electronic structures, electron and thermal transport properties of these low dimensional systems are of our interests. The major theoretical models used in the study of electronic properties are: Tight-binding model, Green’s function methodology, and Landauer formalism. In thermal transport study we employ Molecular Dynamics.
Graphene and Graphene Nanoribbons
A single layer of graphite is recognized as graphene and graphene can be modeled as a one layer infinite 2-D system. Graphene nanoribbons are strips of graphene with infinite length and finite widths. Based on the edge structures, these are known as zigzag and armchair GNRs, and show special electronic properties depending on their edge shape. Zigzag GNRs have zigzag edges and show metallic properties and the armchair GNRs show both metallic as well as semiconducting depending on their widths. The sp2 hybridization of the carbon atoms and link with three nearest-neighbors make the structures strong. Their unique bonding attributes with two-dimensional hexagonal structures make the system important for fundamental physics and in applications. These materials are promising candidates for nanoelectronic devices.
A carbon nanotube (CNT) is a single layer of graphene that is rolled into a seamless cylinder. Based on the ways of rolling the graphene sheet, a particular CNT can be formed and classified as armchair CNT, zigzag CNT, or chiral CNT. CNTs may be single-walled (SWCNT) or multi-walled (MWCNT). The MWCNTs consist of multiple coaxial SWCNT nested within one another. These structures are considered as one-dimensional due to their high length to diameter ratio. CNTs are robust versatile nano-structures that have sparked much interest in the three past decades. Since their discovery by Iijima in 1991 CNTs have been shown to have many interesting physical properties worthy of study.
The BSU research group is investing the phonon dispersion structures and thermal conductivity of CNTs. The numerical simulations are conducted using Visual Molecular Dynamics (VMD), and Large Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS). The LAMMPS code is used on the existing Beowulf Computing Cluster at BSU.
Boron Nitride Materials
Hexagonal boron nitride sheet is an analog of graphene. The only difference is that it is composed of two different elements. Like graphene nanoribbons one can construct boron nitride nanoribbons with two possible edge configurations: Armchair and Zigzag.
We calculate the electronic band structures and analyze their characteristics using tight-binding model and Density Functional Theory (DFT). Dr. Antonio Cancio leads the DFT analyses. This material is an insulator with large band gaps. Our research group is utilizing various tools for reducing the band gaps. If the band gap can be tuned and decreased to the semiconductor regime then this two dimensional boron nitride will be very valuable for device and nano electronic industries.
- K.A. Muttalib, M. Khatun, and J.H Barry, “Perpendicular susceptibility and geometrical frustration in two-dimensional Ising antiferromagnets: Exact soultions,” Phys. Rev B Vol. 96, No 18, 184411 ( 2017)
- Mahfuza Khatun, Zhe Kan, Antonio Cancio, and Chris Nelson, “Effects of Band Hybridization on Electronic properties in Tuning Armchair Graphene Nanoribbons,” Canadian Journal of Physics Vol. 94, No. 2, pp. 218-225 (2016)
- Zhe. Kan, Chris Nelson, and Mahfuza. Khatun, “Quantum conductance of zigzag graphene oxide nanoribbons,” Journal of Applied Physics 115, 153704 (2014).
- M. Khatun, B. D. Padgett, G. A. Anduwan, I. Sturzu, and P. D. Tougaw, “Defect and
Temperature Effects on Complex Quantum-dot Cellular Automata Devices,” Journal of Applied Mathematics and Physics, Published online (htttp://www.scrip.org/journal/jamp), August 15 (2013).
- P. D. Tougaw and M. Khatun, “A Scalable Signal Distribution network for Quantum-dot Cellular Automata,” IEEE Transaction on Nanotechnology, Volume: 12, 2, 215-224 March(2013).
- G. A. Anduwan, B. D. Padgett, M. Kuntzman, M. K. Hendrichsen, I. Sturzu, M. Khatun and P. D. Tougaw, “Fault-tolerance and thermal characteristics of quantum-dot cellular automata devices” J. Appl. Phys. 107, 114306 (2010).
- M. Khatun, I. Sturzu, P. D. Tougaw and T. Barclay “Fault Tolerance Properties in Quantum-dot Cellular Automata Devices,” J. Phys. D: Appl. Phys. 39, 1489-1494 (2006).
- M. Khatun, T. Barclay, P. D. Tougaw and I. Sturzu “Fault Tolerance Calculations for Clocked Quantum-dot Cellular Automata Devices”, Journal of Applied Physics, 98, 094904 (2005).
- E. Mandell and M. Khatun, “Quasi-Adiabatic Clocking of Quantum-Dot Cellular Automata,” J. Appl. Phys. 94, 4116 (2003).
- M. Khatun and J.W. Emert,”Vacancy Migration in the 3-12 Ising Ferromagnet,” Physica Status Solidi B, 231, 341 (2002).
- M. Khatun, P.K. Joyner, R.M. Cosby, and Y.S. Joe, “Quantum Interference in a Stub-Constriction Structure Containing an Infinite Potential Barier,” J. Appl. Phys. 84, 3409 (1998).
- M. Khatun and J. H. Barry, “Exact Solutions for Inelastic Neutron Scattering from Planar Ising Ferromagnets,” Physica A 247, 511 (1997).
- J.H. Barry and M. Khatun, “Exact Solutions for Correlations in the Kagome′ Ising Antiferromagnet,” Int. J. Mod. Phys. B11, 93 (1997).
- J.H. Barry and M. Khatun, "Exact Solutions for Ising-Model Correlations on the 3-12 Lattice," Phys. Rev. B51, 5840 (1995).
- R. Delannay, G. Le Caer, and M. Khatun, "Random Cellular Structures Generated from a 2D Ising Ferromagnet," J. Phys. A: Math. Gen. 25, 6193 (1992).
- J.H.Barry, T. Tanaka, M. Khatun, and C.H. Munera,"Exact Solutions for Odd-Number Correlations on Planar Lattices," Phys. Rev. B44, 2595 (1991).
- M. Fahnle and M. Khatun,"On the Magnetic Contribution to the Free Enthalpy of Vacancy Migration in Ferromagnetic Crystals," Phys. Stat. Sol. A126, 109 (1991).
- M. Khatun, J.H. Barry, and T. Tanaka, "Exact Solutions for Even-Number Correlations of the Square Ising Model," Phys. Rev. B42, 4398 (1990).
- J.H. Barry, M. Khatun, and T. Tanaka, "Exact Solutions for Ising-model Even-number Correlations on Planar Lattices," Phys. Rev. B37, 5193 (1988).
- J.H. Barry and M. Khatun, "Exact Solutions for Perpendicular Susceptibilities of Kagome′ and Decorated Kagome Ising Models," Phys. Rev. B35, 8601 (1987).
During the past three decades, I have been working with many undergraduate and graduate students. Their involvements include working on doctoral thesis, master’s thesis, master’s degree research papers, honors fellowships, honors thesis, and independent research studies. Students worked mainly on different topics: Phase transition and critical phenomena on 2-D Ising models, Electron transport in semiconductor nanodevices, Quantum Dot Cellular Automata (QCA) Devices, Electronic properties and quantum transport of carbon structures (graphene, carbon nanotubes (CNTs), graphene nanoribbons, and boron-nitride nanoribbons.
Tuan Le, Albert DiBenedetto, Spencer Jones, Shaun Wood, Zhe Kan, Benjamin Padgett, Adam Hinkle, Travis Barclay, Melissa Hendrichsen, Luke Kanuchok, Christopher Cochran, Eric Mandell, Gabriel A. Anduwan, Jong-Lae Kim, Philip K. Joyner
Travis Everhart, Albert DiBenedetto, Nick Strange, Andrew Moore, Jeremy Christman, Andrew Moore, David Hines, Joseph Laslie, Josh Gevirtz, Molly Reber, Daniel Baker, Anthony Gilmore, Michael Kuntzman, Elizabeth Cougill, Kyle Crater, Travis Barclay, Michael St. Clair, Thomas Kuhlman, Brian Case, Stayte Wesley, Lisa Pawlowski