My Current Research Activities

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On this page I list a number of research activities in which I am currently active.  Note that in most cases, I collaborate with colleagues, both at ASU, and in other locations, a few of whom are shown below.  I have interests in quite a few topics, diverse in nature, and the listing here is merely the ones in which I have been active during the past year or so.

Summer 2016


The Mesoscopic World

Mesoscopic systems (or devices) are midway between the very small and the large scales, typically from a few nanometers to a few hundred nanometers.  On this scale, and at low temperatures, the quantum properties are readily discovered in measurements of the electronic transport through these structures.  Here, I am focusing on the effects in true two-dimensional materials like graphene and the transition-metal di-chacogenides.

       John Bird, Buffalo

          Yuchi Ochiai, Chiba


         Nobuyuki Aoki, Chiba

Transport in 2D Materials

Graphene is a relatively new material which was isolated only a few years ago, and for which Andre Geim and Konstantin Novoselov recieved the Nobel prize. It is characterized by an very unusual band structure in which there is no gap and the bands are linear at the transition (see image at the right) from valence band to conduction band.  This structure is known as Dirac-like bands, as they are characterized by a zero rest mass Dirac equation.  But, the lack of a bandgap has led to studies of other 2D materials such as MoS2 and WS2.

We study the electron transport through these materials by the use of an ensemble Monte Carlo technique, in which an ensemble of some 100,000 electrons is followed through the material.  Each particle undergoes acceleration in the external electric field and scattering from a variety of sources.  Intrinsic to the material are phonon scattering events due to the acoustic modes and the intervalley optical modes of the lattice.  In addition, we use remote scattering generated by the polar phonons of the substrate material upon which the graphene is place.  We also use impurities, usually remotely located, and defects that give short-range scattering potentials.

With Adre Geim in Mauterndorf, Austria in 2010.

Recent Publications in 2D Materials

D. K. Ferry and I. Welland, “Relativistic Wigner functions in transition metal dichalcogenides,” Journal of Computatinal Electronics 17, 110 (2018) DOI: 10.1007/s10825-017-1094-4

Z. Xiao, J. Song, D. K. Ferry, S. Ducharme, and X. Hong, “Ferroelectric-Domain-Patterning-Control Schottky Junction State in Monolayer MoS2,” Physical Review Letters 118, 236801 (2017) DOI: 10.1103/PhyRevLett.118.236801

D. K. Ferry, “Electron transport in some transition metal di-chalcogenides: MoS2 and WS2,” Semiconductor Science and Technology 32, 085003 (2017) DOI: 10.1088/1361-6641/aa7472

N. Matsumoto, M. Mineharu, M. Matsunaga, C. Chuang, Y. Ochiai, K. Oto, G-H. Kim, K. Watanabe, T. Taniguchi, D. K. Ferry, C. R. da Cunha, and N. Aoki, “Shubnikov-de Haas measurements on a high mobility monolayer graphene flake sandwiched between boron nitride sheets,” Journal of Physics Condensed Matter 29, 225301 (2017) DOI: 10.1088/1361-648X/aa6d36

D. K. Ferry, “Carrier statistics in graphene at high electric field,” Semiconductor Science and Technology 32, 025018 (2017) DOI: 10.1088/1361-6641/aa5143

L. B. Kish and D. K. Ferry, “Information entropy and thermal entropy: apples and oranges,” Journal of Computational Electronics, in press (2017) DOI: 10.1007/s10825-017-1044-1

D. K. Ferry, R. Somphonsone, H. Ramamoorthy, and J. P. Bird, “Energy relaxation of hot carriers in graphene via plasmon interactions,” Journal of Computational Electronics 15, 114 (2016) DOI 10.1007/s10825-015-0764-3

D. K. Ferry, “Density dependence of the saturated velocity in graphene,” Semiconductor Science and Technology 31, 11LT02 (2016) DOI: 1088/0268-1242/31/11/11LT02   

D. K. Ferry, “Electron velocity saturation and intervalley transfer in monolayer MoS2,” Semiconductor Science and Technology 31, 11LT 01 (2016) DOI: 1088/0268-1242/31/11/111LT01

C. R. da Cunha, M. Mineharu, M. Matsunaga, N. Matsumoto, C. Chuang, Y. Ochiai, G.-H. Kim, K. Watanabe, T. Taniguchi, D. K. Ferry, and N. Aoki, “Conductance fluctuations in high mobility monolayer graphene: Nonergodicity, lack of determinism and chaotic behavior,” Scientific Reports 6, 33118 (2016) DOI: 10.1038/srep33118  

D. K. Ferry, R. Somphonsane, H. Ramamoorthy, and J. P. Bird, “Plasmon-mediated energy relaxation in grapheme,” Applied Physics Letters 107, 262103 (2015) DOI: 10.10631/1.4938760   

B. Liu, R. Akis, D. K. Ferry, G. Bohra, R. Somphonsane, H.Ramamoorthy, and J. P. Bird, “Conductance fluctuations in graphene in the presence of long range disorder,” Journal of Physics Condensed Matter 28, 135302 (2016) DOI: 10.1088/0953-8984/28/13/135302

D. K. Ferry, R. Akis, and R. Brunner, “Probing the quantum-Classical Connection with Open Quantum Dots,” Physica Scripta T165, 014010 (2015) DOI: 10.1088/0031-8949/2015/T165/014010


The Heresy I have Spoken:

Perhaps a more fun area is that of challenging the accepted views of the world according to quantum mechanics.  Over the years I have come to believe that Einstein and Schroedinger were correct in that the accepted view, according to Copenhagen, of quantum mechanics was incomplete.  In some sense, this shows up clearly in some of the ideas for quantum computation.  In any case, this had led me to write some heretical papers, in this and other areas, a few of which are:

D. K. Ferry, “Quantum computing and probability,” Journal of Physics Condensed Matter 21, 474201 (2009) doi:10.1088/0953-8984/21/47/474201

D. K. Ferry, “Probing Bell’s inequality with classical systems,” Fluctuation and Noise Letters 9, 395 (2010) DOI: 10.1142/S0219477510000307

D. K. Ferry and L. B. Kish, “Noise and Bell’s theorem,” Fluctuation and Noise Letters 9, 423 (2010) DOI: 10.1142/S0219477510000320

D. K. Ferry, “Feynman on quantum simulation--Rush to judgement,” Journal of Computational and Theoretical Nanoscience 8, 953 (2011) DOI:10.1166/jctn.2011.1775

D. K. Ferry, “Are there quantum jumps,” International Journal of Modern Physics: Conference Series 33, 1460358 (2014) DOI: 10.1142/S2010194514603585

A. P. Kirk and D. K. Ferry, “Photosynthesis vs. photovoltaics,” Journal of Computational Electronics 17, 313 (2018) DOI: 10.1007/s10825-017-1063-y

L. B. Kish and D. K. Ferry, “Information entropy and thermal entropy: apples and oranges” Journal of Computational Electronics 17, 43 (2018) DOI: 10.1007/s10825-017-1044-1

D. K. Ferry, The Copenhagen Conspiracy, in press, to be published by Pan Stanford Publishing, Singapore

© David Ferry 2016