DCMP Image Gallery
click on an image to see a larger version with a caption
If you have an image you would like to see featured, please send it and a caption to the DCMP webmaster at dcmp@bc.edu.
© 2002-2010 Division of Condensed Matter Physics of the American Physical Society
DCMP Home
Computer simulation of electrical conductivity versus magnetic field
directions in the one-dimensional molecular organic conductor (TMTSF)2PF6. Red (blue) regions represent high (low) conductivity,
showing angular magnetoresistance oscillations (AMRO) due to interference between electron waves at commensurate field orientations.
This phenomenon is presently being investigated in micro- and nano-size crystals.
Image courtesy: Pashupati Dhakal, Frank King, Drs. Jeong Il Oh, and Michael J. Naughton, BC Physics Department. |
 |
 top
|
Ground states of a collection of N point-like particles constrained to lie on the surface of a torus and interacting via a cubic potential. The lattices are labeled by (r,N), where r is the ratio between the largest and smallest radius of the torus. The figure shows prominent example of topological defects such as dislcinations (5-fold disclinations are marked in red and 7-fold disclinations in blue), dislocations and grain-boundaries. While in planar crystals these defects are energetically costly and don't appear in the ground state, on a surface of non-zero Gaussian curvature defects proliferate in order to balance the elastic strain introduced by the curvature of the underlying medium.
L. Giomi and M. J. Bowick, Eur. Phys. J. E 27, 275 (2008) &
M. Bowick and L. Giomi, Adv. Phys. 58, 449 (2009).
Image courtesy: Dr. L. Giomi,
School of Engineering and Applied Science,
Harvard University. |
Reflection optical microscope image of the dried suspension of lithographically defined 60-nm-thick, ~1 micron diameter 20:80 ironnickel (permalloy) discs coated with a 5-nm-thick layer of gold on each side that possess a spin-vortex ground state. Under application of an alternating magnetic field the spin vortices shift, creating an oscillation. When the microdiscs are biofunctionalized and selectively attached to the cancer cell, such spin-vortex-mediated stimulus creates two dramatic effects: compromised integrity of the cellular membrane, and initiation of programmed cell death. Nature Materials, doi:10.1038/nmat2591.
Image courtesy: Dr. V. Novosad, Argonne National Laboratory. |
|
 |
A current image is taken at 50meV in the twin domain boundary of underdoped Ca(Fe1-xCox)2As2. The static unidirectional electronic structures change directionality by 90 degrees across the twin boundary. The autocorrelations of the respective domains are shown in the insets; center of self-similarity peaks (gray lines) are separated by ~8aFe-Fe.
T.-M. Chuang, M. P. Allan, Jinho Lee, Yang Xie, Ni Ni, S. L. Budko, G. S. Boebinger, P. C. Canfield, J. C. Davis. Science 327, 181 (2010).
Image courtesy: Dr. J.C. Seamus Davis, Cornell University. |
top
The AFM study of a human cell, in which cells are treated as just soft elastic material coated with soft brush. The authors found a unique feature of cervical cancer cells this way. A collage of the special AFM and SEM probes of cells is shown. Small (Nano/Micro) 5(20), 2277 (2009).
Image courtesy: Dr. I. Sokolov, Clarkson University. |
|
 |
The first proof that the large-scale shape of nanoporous particles can be described by equilibrium thermodynamics. Various synthesized shapes are shown.
Volkov, D., J. Benson, Y. Kievsky, I. Sokolov, Phys. Chem. Chem. Phys. 12, 341 (2010), DOI: 10.1039/b917424a.
Image courtesy: Dr. I. Sokolov, Clarkson University. |
A new representation of topological defects in smectic liquid crystals that captures both
broken translational and rotational symmetry. B.G. Chen, G.P. Alexander, and R.D. Kamien, Proc. Natl. Acad. Sci. USA 106, 15577, doi: 10.1073/pnas.0905242106 (2009).
Image courtesy: Dr. R.D. Kamien, University of Pennsylvania, designer - Bryan Chen.
|
|
top
 |
The conventional unit cell of the diamond crystal lattice.
Image courtesy: Dr. Axel Lorke, University of Duisburg-Essen, Germany. |
A Schrödinger's cat state is detected in superconducting nanowires at high bias currents through the analysis of the statistics of the switching currents. It is demonstrated that at high bias currents the entire number of superconducting electrons in an ultrathin superconducting wire can quantum-mechanically tunnel from a state having a higher electrical current to one having a lower current. Since the effect involves a large number of electrons it is called macroscopic quantum tunneling (MQT). Another term used to describe such tunneling is quantum phase slip (QPS). Unlike in previous reports on superconducting nanowires, here the conclusion about the presence of QPS is reached by measuring and analyzing the fluctuation of the switching current at T=0.3 K.
M. Sahu, M.-H. Bae, A. Rogachev, D. Pekker, T.-C. Wei, N. Shah, P. M. Goldbart and A. Bezryadin, Nature Physics 5, 503 (2009).
Image courtesy: Dr. A. Bezryadin, UIUC.
|
 |
|
Surface geometry of C60 on Ag(111) surface. The stable monolayer C60 molecules sit on vacancy sites with an Ag(111)-(2 x2 )R30o-C60 structure. The hexagon of the C60 molecule is facing down to the Ag surface. There are two such parallel orientations of the molecules, one as shown, and one rotated 180 deg. The top hexagon is surrounded by 3 hexagons and 3 pentagons -180 deg rotation interchanges these (as well as some others that are not visible). There is a small deformation of the substrate near the location of the C60 molecule, as seen in the front view. Top: top view, Bottom: front view.
H. I. Li, K. Pussi, K. J. Hanna, L.-L. Wang, D.D. Johnson, H.-P. Cheng, H. Shin, S. Curtarolo, W. Moritz, J.A. Smerdon, R. McGrath, and R.D. Diehl, Phys. Rev. Lett. 103, 056101 (2009).
Image courtesy: H.I. Li and R.D. Diehl, Pennsylvania State University. |
top
A human hair into which the logo of the Center for Nanointegration Duisburg-Essen (CeNIDE) was engraved using a focused ion beam (FIB).
Image courtesy: Dr. A. Lorke, University of Duisburg-Essen,
Germany.
|
|
 |
Three-dimensional rendering of the electric field from numerical calculations in a random laser in which the yellow spheres represent the nanoparticles in a cylindrically symmetric gain medium. The electric field, where color and height indicate intensity, represents the steady-state solution of the Maxwell-Bloch system of equations.
Hakan E. Türeci, A. Douglas Stone, Li Ge, Stefan Rotter, and Robert J. Tandy.
"Ab initio self-consistent laser theory and random lasers," Nonlinearity 22, C1C18 (2009).
Image courtesy: Dr. Robert Tandy, Yale University.
|
Relative vorticity of simulated barotropic flow on a rotating sphere that shows the formation of jets and also structures at mid to high latitudes. Coordinate singularities at the poles are avoided by the use of a spherical geodesic grid with 163,842 cells.
J. B. Marston, E. Conover, and Tapio Schneider. "Statistics of an Unstable Barotropic Jet from a Cumulant Expansion," arXiv:0705.0011, J. Atmos. Sci. 65, 1955 (2008).
Image courtesy: Dr. J. B. Marston, Brown University.
|
 |
top
 |
A scanning electron microscope (SEM) image of the molecular organic superconductor (TMTSF)2ClO4 (green), contacted with five Pt nanowires (yellow) and Au micro-electrodes (gold) using focused ion-beam and electron beam lithography deposition in the Boston College Nanofabrication Clean Room. This allows us to study "finite size effects" in micro- and nano-scale correlated electron systems, when surface physics begin to dominate over volume effects.
Image courtesy: Dr. M.J. Naughton, Dr. J.I. Oh, and Pashupati
Dhakal, Boston College.
|
Ge/Si core/shell nanowire heterostructures, when coupled to superconducting leads, are tunable mesoscopic Josephson junctions. The underlying plot is a map of the differential conductance as a function of both gate and source-drain voltage, with multiple Andreev reflections giving rise to the observed pattern.
Andy Vidan, MIT Lincoln Laboratory.
Nature Nanotechnology 1, 208 (2006).
Image courtesy: Dr. Andy Vidan, MIT Lincoln Laboratory.
|
 |
 |
A post-rendered image of the variations in the electronic cluster glass (ECG) in underdoped Na-CCOC.
J.C. Seamus Davis, Cornell University; H. Takagi, RIKEN, University of Tokyo, and S. Uchida, University of Tokyo.
Cover Article:
Science 315, 5817 (2007).
Image courtesy: Dr. J.C. Seamus Davis, Cornell University.
|
top
Boron nitride nanotubes are materials whose existence theorists predicted before they were synthesized in laboratories. The pictured image is a simulation of a single nanotube. This material has the intriguing property that the greatest density of conduction electrons is along the tube axis. Boron nitride nanotubes thus can ballistically conduct electrons down the center of the tube.
Marvin L. Cohen, University of California, Berkeley. Physics Today 59 (6), 48 (2006). ©2006, American Institute of Physics.
Image courtesy: Dr. Marvin L. Cohen, University of California, Berkeley.
|
 |
 |
A model of the spin-triplet, organic superconductor (TMTSF)2PF6.
Image courtesy: Dr. M.J.Naughton, Boston College. |
Low-energy Wannier states (WS) of real materials.
Top: Gapless excitations in the charge density wave phase of TaSe2 is explained with the unique geometric effects derived naturally from the phase interference of the WS. The hyrdization of 'ag and eg' symmetry essential to the understanding is clearly observed. (Phys. Rev. Lett. 96, 026406 (2006)).
Bottom: Unexpectedly strong spin-dependence of resonant inelastic x-ray spectrum of LaMnO3 is explained by the strong charge transfer nature of LaMnO3, which is directly observable from the large hybridization with O-p states in the WS. Based on further novel WS analysis, origin of orbital ordering of MnF3 and LaMnO3 is, surprisingly, mainly electron-electron interaction, rather than the electron-phone coupling (Jahn-Teller effects). (Phys. Rev. Lett. 94, 047203 (2005) & cond-mat/0509075).
Image courtesy: Dr. Wei Ku,
Brookhaven National Lab. |
|
top
 |
An array of aligned, but randomly placed, carbon nanotubes which can act like a radio antenna for detecting light at visible wave-lengths. The scale bar is one micron in length.
K. Kempa, Z. Ren et al., Appl. Phys. Lett. 85, 13 (2004).
Image courtesy: Dr. K. Kempa, Boston College.
|
A single-walled carbon nanotube of 75 nanometers can stretch to 84 nanometers before it breaks.
J. Y. Huang, S. Chen, Z. Q. Wang, K. Kempa, Y. M. Wang, S. H. Jo, G. Chen, M. S. Dresselhaus, Z. F. Ren. Nature 439, 281 (2006).
Image courtesy: Dr. J. Huang, SNL. |
 |
 |
Scanned gate microscopy image of single electron charging in a nanotube quantum dot. The conductance of the dot is measured at low temperatures as an electrically biased AFM tip is scanned over it. The ridges correspond to Coulomb oscillations where the charge state of the dot changes by one electron.
M.T. Woodside and P.L. McEuen, Science 296, 1098 (2002).
Image courtesy: Dr. Paul L. McEuen, Cornell University.
|
top
Schematic of single atom transistors. A metal coordination complex containing a single cobalt atom is attached to gold electrodes. Transport through the molecule is used to probe single electron charging, the Kondo effect, and the vibrational properties of the molecules.
Jiwoong Park, Abhay N. Pasupathy, Jonas I. Goldsmith, Connie Chang, Yuval Yaish, Jason R. Petta, Marie Rinkoski, James P. Sethna, Hector D. Abruna, Paul L. McEuen, and Daniel C. Ralph. Nature 417, 722 (2002).
Image courtesy: Drs. James P. Sethna, Paul L. McEuen, Cornell University.
|
|
 |
The surface of a 4 µm-thick GaSb film
grown on a GaAs(001) substrate by molecular beam epitaxy. The image, with a
field of view of approximately
1 µm, reveals the nanometer-scale morphology of the spiral-like
structures that grow around threading dislocations in the film (caused by
the film's 7% lattice mismatch with the substrate). Each threading
dislocation creates a 0.3 nm-height "step" where it emerges at the surface.
P. M. Thibado, B. R. Bennett, B. V. Shanabrook, and L. J. Whitman.
Image courtesy: Dr. L. J. Whitman, NRL.
|
|
Atomic force microscopy (AFM) image of lead
disulfide microcrystals grown on a silicon oxide surface patterned by the AFM
using "Dip-pen Nanolithography" (DPN).
The field of view is 11.6 µm across, and the hexagonal crystallites
are about 60 nm high. DPN was used to write a 5 µm x 5µm
chemically-reactive region on the wafer, which was then soaked in lead acetate
and exposed to H2S gas. Microcrystals selectively grew starting
from the patterned area.
S. E. Kooi, L. A. Baker, P. E. Sheehan, and L. J. Whitman.
Image courtesy: Dr. L. J. Whitman, Naval Research Laboratory.
|
|
top
 |
Theoretical flow of electrons in a two dimensional electron gas away from an electron source at the center. The same scattering that produces diffusion creates static branches of electron flow.Cover Article: Nature 410, 6825 (2001).
Image courtesy: Dr. Eric Heller, Harvard University.
|
|
This image shows the coherent flow of electrons through a quantum point contact formed in a two dimensional electron gas inside a GaAs/AlGaAs heterostructure. Scanned probe microscope images on the outside agree well with theoretical simulations inside. The fringes are spaced by half the electron wavelength.
Robert Westervelt and Eric Heller at Harvard University, Arthur C. Gossard at UC Santa Barbara, Physics Today 56(12) (2003).
Image courtesy: Dr. Eric Heller, Harvard University.
|
|
 |
SEM images of hierarchical ZnO nanostructures with basic 6-fold (first row), 4-fold (second row), and 2-fold (third row) symmetry made by thermal vapor transport and condensation technique. The primary core nanowires are either pure In2O3 or In2O3-doped ZnO, whereas the secondary branch nanowires are pure ZnO.
Z. Ren, J. Lao, and J. Wen.
Nano Lett. 2(11) (2002) .
Image courtesy: Dr. Z. Ren, Boston College. |
top
Scanned probe microscope image of electrons in a two dimensional electron gas inside a GaAs/AlGaAs heterostructure at a low temperature. A strong magnetic field produces the quantum Hall effect, and causes the patterns shown.
Raymond Ashoori, MIT, Physics Today 56(12) (2003).
Image courtesy: Dr. Raymond Ashoori, MIT.
|
|
 |
Scanned probe microscope images of electron flow away from a quantum point contact formed in a two dimensional electron gas inside a GaAs/AlGaAs heterostructure. Small angle scattering causes branches of electron flow to form at distances less than the mean free path.
Robert Westervelt, Harvard University,
Arthur C. Gossard, UC, Santa Barbara, Physics Today 56(12) (2003).
Image courtesy: Dr. Robert Westervelt, Harvard University.
|
Computed flow of electrons away from a quantum point contact in a two dimensional electron gas with small angle scattering. The potential which scatters electrons is shown, together with the calculated flow, which forms branches at distances less than the mean free path. Physics Today 56 (12) (2003).
Image courtesy: Dr. Eric Heller, Harvard University. |
|
top
|
Transmission electron microscope image of chemically produced cobalt nanomagnets in the form of spheres and rods. The nanorods align with an applied magnetic field indicating that they are ferromagnetic.
Image courtesy: Dr. Moungi Bawendi, MIT.
|
Spinscape:
Electron-spin data from a spin-shifting microstructure shows variations from almost no spin (flat regions) to rapid spin (ridges) in a particular direction.
Y. Kato, R. C. Myers, D. C. Driscoll, A. C. Gossard, J. Levy, D. D. Awschalom. Science News 163(8) (2003).
Image courtesy: Dr. D. D. Awschalom, University of California, Santa Barbara.
|
|
|
Theoretical potential-energy surface for Mn adsorption on GaAs(001),
calculated within density-functional theory.
Phys. Rev. Lett. 89, 227201 (2002).
Image courtesy: Dr. Steven C. Erwin,
Naval Research Laboratory.
|
top
Scanning electron micrograph (SEM) of a part of the skeleton of a brittlestar Ophiocoma wendtii (Ophioroidea, Echinodermata). The entire structure (the mesh and the array of microlenses) is composed of a single calcite crystal used by the organism for mechanical and optical functions.
Joanna Aizenberg, David A. Muller, John L. Grazul, D. R. Hamann. Science 299, 1205 (2003).
Image courtesy: Dr. Joanna Aizenberg, Harvard. |
|
|
The local electronic quantum state at a single Zn
impurity atom in Bi-2212 superposed on an image of the BiO surface underneath which this quantum state exists.
J.C. Seamus Davis,
Cornell University and S. Uchida, Tokyo University.
Image courtesy: Dr. J.C. Seamus Davis,
Cornell University.
|
An image of a ~120 angstrom square region of the BiO
surface of the high Tc superconductor Bi-2212.
Image courtesy: Drs. J.C. Seamus Davis,
Cornell University and S. Uchida, Tokyo University.
|
|
top
|
Spin interference in
GaAs 2D holes - Observation of Berry's Phase via Aharonov-Bohm measurements
Image courtesy: Dr. Mansour Shayegan,
Princeton University.
|
|
An experimental demonstration of how doping changes the
band positions relative to Fermi level, key to semiconductor device
fabrication. This is the first direct demonstration of this effect in a
polymeric semiconductor.
Peter Dowben, Appl. Phys. Lett. 80, 4342 (2002).
Image courtesy: Dr. Peter Dowben,
University of Nebraska. |
|
|
One jump, or avalanche, in our model for crackling noise in magnets. The first spins to flip are colored blue, and the last pink. Notice the fractal structure: the avalanche is rough on all time scales.
James P. Sethna, Karin A. Dahmen, Christopher R. Myers.
Nature 410, 242-250 (2001).
Image courtesy: Dr. James P. Sethna, Cornell University.
|
top
Layout of a pi-SQUID which
makes use of the d-wave symmetry of the macroscopic order parameter of
high-Tc superconductors for device-applications. The pi-SQUID has been
realized with the bicrystal-technology.
Schulz, Chesca, Goetz, Schneider, Schmehl, Bielefeldt,
Hilgenkamp, Mannhart, and Tsuei. Appl. Phys. Lett. 76, 912 (2000).
Image courtesy: Dr. Jochen Mannhart, University of Augsburg, Germany.
|
|
|
Atomic force microscopy image of a single silicon adatom,
size 660 pm x 660 pm x 120 pm. The two crescents are interpreted to
represent two orbitals originating in a single tip atom.
Giessibl, Hembacher, Bielefeldt and Mannhart. Science 289, 422
(2000).
Image courtesy: Drs. Jochen Mannhart,
Franz Giessibl, University of Augsburg, Germany.
|
19 electrons trapped in a spherical electric field. They form shells like atoms in the periodic table (notice the symmetry),
and they may "freeze," i.e. crystallize like in this figure. Phys. Rev. Focus
(2001).
Image courtesy: Dr. Michael Bonitz, University of Kiel, Germany. |
|
top
|
Quasicrystals.
Crystals are surely the oldest known of the broken-symmetry phases of matter, and remain the most beautiful illustrations. It's amazing that in the past few years, we've uncovered an entirely new class of crystals. Shown here is a photograph of a quasicrystalline metallic alloy, with icosahedral symmetry. Notice the five-pointed stars: our old notions of crystals had to be completely revised to include this type of symmetry.
J. H. Lang, M. Audier, B. Dubost, and P. Sainfort, J. of Crystal Growth 83, 456 (1987).
Image courtesy: Drs. Marc Audier, James P. Sethna, Cornell University.
|
|
