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Mildred S. Dresselhaus

Bio: Mildred S. Dresselhaus is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Carbon nanotube & Raman spectroscopy. The author has an hindex of 136, co-authored 762 publications receiving 112525 citations. Previous affiliations of Mildred S. Dresselhaus include University of California, Los Angeles & Universidade Federal de Minas Gerais.


Papers
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Journal ArticleDOI
TL;DR: In this article, a turning point appeared to occur when the number of women reached a critical mass of about 10-15% of the students in a class at MIT, where women participated more and more in class discussions.
Abstract: When I started teaching solid‐state‐physics courses at MIT, nearly 20 years ago, there were very few women at MIT and very few women students in my classes. It was unusual for women students to ask questions in class or to participate in class discussions. As the number of women students increased, they participated more and more, and in very recent years their class participation has become essentially indistinguishable from that of the men. A turning point appeared to occur when the number of women reached a “critical mass” of about 10–15% of the students in a class. But in some other physics courses at MIT the critical mass hasn't been reached.

9 citations

Journal ArticleDOI
TL;DR: In this paper, the temperature variation of the thermal conductivity and the thermopower of intercalated benzene-derived carbon fibres are discussed and the lattice thermal conductivities are separated from the electronic term, revealing an extra contribution in the lowest temperature range.

8 citations

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TL;DR: In this paper, the implantation and annealing conditions required to introduce and retain impurities in the graphite lattice have been studied using the backscattering-channeling technique.
Abstract: The implantation and annealing conditions required to introduce and retain impurities in the graphite lattice have been studied using the backscattering-channeling technique. When highly oriented pyrolytic graphite (HOPG) is implanted at room temperature, the damage caused by the implantation can be completely annealed by heating the sample to temperatures Ta ≳ 2500°C. As the temperature is raised, the first recrystallization (graphitization) step involving two-dimensional or in-plane ordering occurs for annealing temperatures in the range 1500°C ≲ Ta ≲ 2300°C. In this range, the impurities diffuse parallel to the basal planes and out of the sample. This ejection of the implanted species appears to be correlated with a decrease in the interplanar spacing of the graphite structure during the graphitization process. A second step of graphitization occurs at temperatures higher than 2300°C where three-dimensional or c-axis ordering takes place. However at these high temperatures all the impurities have already diffused out of the substrate. Retention of the impurities and simultaneous annealing of radiation defects can be achieved when the sample is implanted at an elevated temperature (200 < Ti < 800°C) and subsequently annealed at ∼ 2300°C. However this behavior depends on the implanted species; e.g., As ions are retained by the graphite lattice after post-hot-implantation annealing while no trace of Si implants can be found after the same implantation and annealing procedure.

8 citations

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TL;DR: In this article, it was shown that the monotonic component of the σ(T) dependence can be satisfactorily approximated by theoretical calculations based on the classical Fuchs - Sondheimer theory.
Abstract: The room-temperature dependences of the electrical conductivity σ, Seebeck coefficient S, Hall coefficient RH, and the thermoelectric power factor P on the thickness (d=10–300 nm) of the thin films grown on mica substrates by thermal evaporation in vacuum of Bi-Sb solid solutions crystals with 4.5 at.% Sb were obtained. It was established that an increase in d up to ~ 200 nm leads to a change in kinetic coefficients and that in the thickness dependences of the thermoelectric properties, quantum oscillations were observed. It was shown that the monotonic component of the σ(T) dependence can be satisfactorily approximated by theoretical calculations based on the classical Fuchs - Sondheimer theory. The theoretically estimated period of oscillations is in a good agreement with the experimentally observed period.

8 citations

Journal Article
TL;DR: In this paper, the authors used Raman spectroscopy and first-principles theory to report their findings related to low-frequency (LF) interlayer breathing modes (<100 cm1) in few-layer BP for the first time.
Abstract: As a new two-dimensional layered material, black phosphorus (BP) is a promising material for nanoelectronics and nano-optoelectronics. We use Raman spectroscopy and first-principles theory to report our findings related to low-frequency (LF) interlayer breathing modes (<100 cm1) in few-layer BP for the first time. The breathing modes are assigned to Ag symmetry by the laser polarization dependence study and group theory analysis. Compared to the high-frequency (HF) Raman modes, the LF breathing modes are much more sensitive to interlayer coupling and thus their frequencies show much stronger dependence on the number of layers. Hence, they could be used as effective means to probe both the crystalline orientation and thickness for fewlayer BP. Furthermore, the temperature dependence study shows that the breathing modes have a harmonic behavior, in contrast to HF Raman modes which are known to exhibit anharmonicity.

8 citations


Cited by
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Journal ArticleDOI
22 Oct 2004-Science
TL;DR: Monocrystalline graphitic films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands and they exhibit a strong ambipolar electric field effect.
Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.

55,532 citations

Journal ArticleDOI
Sumio Iijima1
01 Nov 1991-Nature
TL;DR: Iijima et al. as mentioned in this paper reported the preparation of a new type of finite carbon structure consisting of needle-like tubes, which were produced using an arc-discharge evaporation method similar to that used for fullerene synthesis.
Abstract: THE synthesis of molecular carbon structures in the form of C60 and other fullerenes1 has stimulated intense interest in the structures accessible to graphitic carbon sheets. Here I report the preparation of a new type of finite carbon structure consisting of needle-like tubes. Produced using an arc-discharge evaporation method similar to that used for fullerene synthesis, the needles grow at the negative end of the electrode used for the arc discharge. Electron microscopy reveals that each needle comprises coaxial tubes of graphitic sheets, ranging in number from 2 up to about 50. On each tube the carbon-atom hexagons are arranged in a helical fashion about the needle axis. The helical pitch varies from needle to needle and from tube to tube within a single needle. It appears that this helical structure may aid the growth process. The formation of these needles, ranging from a few to a few tens of nanometres in diameter, suggests that engineering of carbon structures should be possible on scales considerably greater than those relevant to the fullerenes. On 7 November 1991, Sumio Iijima announced in Nature the preparation of nanometre-size, needle-like tubes of carbon — now familiar as 'nanotubes'. Used in microelectronic circuitry and microscopy, and as a tool to test quantum mechanics and model biological systems, nanotubes seem to have unlimited potential.

39,086 citations

Journal ArticleDOI
TL;DR: Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena can now be mimicked and tested in table-top experiments.
Abstract: Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.

35,293 citations

01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.

29,323 citations

Journal ArticleDOI
TL;DR: In this paper, the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations, are discussed.
Abstract: This article reviews the basic theoretical aspects of graphene, a one-atom-thick allotrope of carbon, with unusual two-dimensional Dirac-like electronic excitations. The Dirac electrons can be controlled by application of external electric and magnetic fields, or by altering sample geometry and/or topology. The Dirac electrons behave in unusual ways in tunneling, confinement, and the integer quantum Hall effect. The electronic properties of graphene stacks are discussed and vary with stacking order and number of layers. Edge (surface) states in graphene depend on the edge termination (zigzag or armchair) and affect the physical properties of nanoribbons. Different types of disorder modify the Dirac equation leading to unusual spectroscopic and transport properties. The effects of electron-electron and electron-phonon interactions in single layer and multilayer graphene are also presented.

20,824 citations