168 research outputs found

    Frontiers of Material Research

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    (This information was taken from the Distinguished Scientist Lecture Series Program 1989-1990). Dr. Dresselhaus is currently Institute Professor at the Massachusetts Institute of Technology. She was formerly the holder of the Abby Rockefeller Mauze Chair in Electrical Engineering and in Physics at MIT. She is also affiliated with the Center for materials and Engineering, and with the Francis Bitter National Magnet Laboratory at MIT where some of the experimental work of her group is carried out. Dr. Dresselhaus holds professorships in MIT\u27s Department of Electrical Engineering and Computer Science and the Department of Physics. Dr. Dresselhaus was born in Brooklyn and recieved her A.B. from Hunter College in 1951, graduation Summa Cum Laude. From 1951 to 1952, she was a Fulbright Fellow at Newnham College, Cambridge University, and was awarded an A.M. from Radcliffe College in 1953. She received her Ph.D. from the University of Chicago in 1958. Dr. Dresselhaus was a NSF Postdoctoral Fellow at Cornell University from 1958-60, and Staff Member at the MIT Lincoln Laboratory from from 1967-70. She has traveled widley as a visiting professor, as a visiting professor, holding that position in the Department of Physics of the University of Campinas (Brazil), in the summer of 1971 as well as the physics departments of the Israel Institute of Technology in Haifa, Israel (1972), the Aoyama Gakuin Universityand Nihon University in Tokyo, Japan (1973), and the Instituto Venezolano de Investigaciones Ceintificas in Caracas, Venezuela (1977). Dr. Dresselhaus received many honorary degrees and awards, among them the Hunter College Hall of Fame Award in 1972, the MIT Killian Faculty Award in 1986, and the Annual Achievement Award from the Engineering Societies of New England in 1988. She was elected to the American Academy of Arts and Sciences (1974), the National Academy of Engineering (1974) and the National Academy of Science (1985). Dr. Dresselhaus was a member of the Committee on the Education and Employment of Women in Science and Engineering of the Commission on Human Resources, National Research Council, from 1975-77, and in 1984 served as President of the American Physical Society. She is a senior member of the Society of Women Engineers, and was elected member of the Harvard Alumni Board of Directors from 1974-77. She was on the editorial board of the Physical Review B from 1979-81. and in 1988 became a trustee of the Rensselaer Polytechnic Institute. Her Work: Dr. Dresselhaus has used and developed a wide range of techniques to study condensed matter physics, from microwave properties of superconductors to magnetic phases in semiconductors, and electronic structure of group V semimetals and graphite.https://digitalcommons.bard.edu/dsls_1989_1990/1001/thumbnail.jp

    Resonant Tunneling and Intrinsic Bistability in Twisted Graphene Structures

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    We predict that vertical transport in heterostructures formed by twisted graphene layers can exhibit a unique bistability mechanism. Intrinsically bistable II-VV characteristics arise from resonant tunneling and interlayer charge coupling, enabling multiple stable states in the sequential tunneling regime. We consider a simple trilayer architecture, with the outer layers acting as the source and drain and the middle layer floating. Under bias, the middle layer can be either resonant or non-resonant with the source and drain layers. The bistability is controlled by geometric device parameters easily tunable in experiments. The nanoscale architecture can enable uniquely fast switching times.Comment: 7 pages, 4 figure

    Ab initio study of electron-phonon interaction in phosphorene

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    The monolayer of black phosphorous, or phosphorene, has recently emerged as a new 2D semiconductor with intriguing highly anisotropic transport properties. Existing calculations of its intrinsic phonon-limited electronic transport properties so far rely on the deformation potential approximation, which is in general not directly applicable to anisotropic materials since the deformation along one specific direction can scatter electrons traveling in all directions. We perform a first-principles calculation of the electron-phonon interaction in phosphorene based on density functional perturbation theory and Wannier interpolation. Our calculation reveals that 1) the high anisotropy provides extra phase space for electron-phonon scattering, and 2) optical phonons have appreciable contributions. Both effects cannot be captured by the deformation potential calculations.Comment: 25 pages, 15 figure

    Enhanced thermionic-dominated photoresponse in graphene Schottky junctions

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    Vertical heterostructures of van der Waals materials enable new pathways to tune charge and energy transport characteristics in nanoscale systems. We propose that graphene Schottky junctions can host a special kind of photoresponse which is characterized by strongly coupled heat and charge flows that run vertically out of the graphene plane. This regime can be accessed when vertical energy transport mediated by thermionic emission of hot carriers overwhelms electron-lattice cooling as well as lateral diffusive energy transport. As such, the power pumped into the system is efficiently extracted across the entire graphene active area via thermionic emission of hot carriers into a semiconductor material. Experimental signatures of this regime include a large and tunable internal responsivity R{\cal R} with a non-monotonic temperature dependence. In particular, R{\cal R} peaks at electronic temperatures on the order of the Schottky potential ϕ\phi and has a large upper limit Re/ϕ{\cal R} \le e/\phi (e/ϕ=10A/We/\phi=10\,{\rm A/W} when ϕ=100meV\phi = 100\,{\rm meV}). Our proposal opens up new approaches for engineering the photoresponse in optically-active graphene heterostructures.Comment: 6 pages, 2 figure

    Breit-Wigner-Fano lineshapes in Raman spectra of graphene

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    Excitation of electron-hole pairs in the vicinity of the Dirac cone by the Coulomb interaction gives rise to an asymmetric Breit-Wigner-Fano lineshape in the phonon Raman spectra in graphene. This asymmetric lineshape appears due to the interference effect between the phonon spectra and the electron-hole pair excitation spectra. The calculated Breit-Wigner-Fano asymmetric factor 1/qBWF as a function of the Fermi energy shows a V-shaped curve with a minimum value at the charge neutrality point and gives good agreement with the experimental result.Comment: 15 pages, 4 figure

    Origin of electronic Raman scattering and the Fano resonance in metallic carbon nanotubes

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    Fano resonance spectra for the G band in metallic carbon nanotubes are calculated as a function of laser excitation energy in which the origin of the resonance is given by an interference between the continuous electronic Raman spectra and the discrete phonon spectra. We found that the second-order scattering process of the non-zero q electron-electron interaction is more relevant to the continuous spectra rather than the q = 0 first-order process because the q = 0 direct Coulomb interaction vanishes due to the symmetry of the two sublattices of a nanotube. We also show that the RBM spectra of metallic carbon nanotubes have an asymmetric line shape which previously had been overlooked.Comment: 5 pages, 5 figures, submitted to Physical Review Letters on February 4, 201

    Mildred Dresselhaus edited transcript, part III, 1976 June–August

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    For more information about this item, visit https://archivesspace.mit.edu/repositories/2/archival_objects/30837

    Mildred Dresselhaus edited transcript, part I, 1976 June–August

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    For more information about this item, visit https://archivesspace.mit.edu/repositories/2/archival_objects/30837
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