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Condensed Matter Experiment
FacultyRobert Anderson, ProfessorS. M. Bhagat, Professor Dennis Drew, ProfessorEllen Williams, ProfessorMichael Fuhrer (with CSR), Assistant ProfessorMin Ouyang, Assistant ProfessorRobert Park, Professor (APS – “What’s New”)Richard Webb, Professor (with CSR) (on leave)
Affiliated Faculty (LPS)D. Romero B. KaneK. SchwabB. Barker
Condensed Matter Experiment
FacultyRobert Anderson, Professor RS. M. Bhagat, Professor TDennis Drew, Professor REllen Williams, Professor RMichael Fuhrer (with CSR), Assistant Professor (Hired 1999)Min Ouyang, Assistant Professor (Hired 2004)Robert Park, Professor (APS – “What’s New”)Richard Webb, Professor (with CSR) (on leave)
Affiliated Faculty (LPS)D. Romero B. KaneK. SchwabB. Barker
Condensed Matter Experiment
3 March 2005
Post-docs 12 (+3 LPS) RGAs 22 (+12 LPS) Undergrads 4 (+1 LPS) Research Scientists 4 visitors (> 1 month) 2 Publications (2000-2005) 108 Invited talks (2000-2005) 99 Present Annual Funding $3,412,050 Funding Sources NSF-MRSEC, NSF-NIRT
NSF, ARL, ARO, NSA NIST, NRL, DOE, CSR Northrop-Grumman
US News ranking: 10
OutlineQuantum properties at the nanoscale to mesoscale
(CME, CSR, LPS; Anderson, Drew, Lobb, Wellstood, Webb, Ouyang, Fuhrer, Kane, Schwab, Barker)
Applied Statistical Mechanics: properties at the nanoscale(CME, IPST; Williams, Weeks, Das Sarma, Einstein)
Low-Dimensional Interfaces: Organic and Inorganic materials, molecular electronics (CME, Chemistry; Fuhrer, Lee, Reutt-Robey, DeShong, Ouyang, Sita, Williams)
Nanophysics: Nanoscale imaging, devices, assembly (CME, EE, Materials, LPS; Drew, Fuhrer, Gomez, Lee, Phaneuf, Williams)
Magnetic Oxides: Dilute magnetic oxides, multiferroics and high TC superconductivity(CME, CSR, Materials, NIST, Rutgers); Bhagat, Drew, Greene, Ogale, Takeuchi, Venkatesen, Lynn, Cheong)
Maryland Infrastructure• NSF-Materials Research Science and Engineering
Center Interdisciplinary, competitively funded research center,
Collaborative research programs; Shared Experimental Facilities, Educational and Industrial Outreach Programs. Director: Ellen Williams
• Center for Superconductivity Research Established as a state-supported research laboratory in 1988.
Director, Prof. R. Greene. • Institute for Physical Science and Technology
State-supported interdisciplinary research institute. Strengths in non-linear dynamics, statistical mechanics, applied mathematics, space physics. Director, R. Roy.
• Maryland Center for Integrated Nano-Science and Engineering/ Kim Building
State-supported research center to for research and applications of nanotechnology. Director: G. Rubloff
• Laboratory for Ion Beam Research and Applications Focused Ion Beam research and application
• Laboratory for Physical Science Neighboring DoD Laboratory with 20+ year history of support
for condensed Matter Physics at UMD. Director: Bernadette Preston
History: UMD Nanotechnology FlagshipPhysics Liaison - E. Williams (1998-present) + M. Fuhrer (2004-present)
• 1998: Chair- Steve Wallace, Acting Dean - John Osborne Proposal in parallel with Engineering proposal. Requested infrastructure support + 2
faculty hires Result - Michael Fuhrer recruited in 1999
• 1999: Chair - Jordan Goodman, Dean - Steve Halperin Proposal submitted by Engineering with one hire in Physics endorsed by CMPS Result – not approved
• November 2000: Chair - Jordan Goodman, Dean - Steve Halperin endorse proposal for three Nanotechnology hires in CMPS to be included in joint Engineering/CMPS Initiative. Search is initiated, then cancelled by the Dean.
• Fall 2003: University provides a new line in physics to be used for a nanoscience hire
Result: Min Ouyang hired in 2004• 2003-2004 IPST undertaking facilities renovation in preparation for two
experimental biophysics hires. Candidates selected in biophysics search (chair: E. Williams) to be presented to Physics faculty March 10.
• 2004 Dean of Engineering - Nariman Farvardin proposes a major initiative in Nanoscience/Nanotechnology to be coordinated through IREAP in conjunction with new Nanofabrication facility in Kim Bldg. P. O’Shea appointed director of Nanoscience and G. Rubloff director of M-CINSE (Maryland Center for Integrated Nanoscience and Engineering).
http://www.physics.umd.edu/cal/spevents/nanoscience/index.html
Nanophysics & Devices:LPS Program Overview
H.D. Drew, M.S. Fuhrer, S.B. Lee, J. Melngailis, R.J. Phaneuf, E.D. Williams, M. Zachariah
Collaborations: P. Abshire, R. Ghodssi, R. Gomez, E. Smela, D. Romero, G. Rubloff
• Program focus: Develop and evaluate advanced nano-optical and nano-electronic technologies for sensing and information processing. Nano-electronics with carbon nanotubes and innovative nanotube
materials (Fuhrer, Lee, Melngailis) Nanoparticle-enhanced fluorescence for sensing applications
(Phaneuf, Zachariah, Drew) Integration of nano-electronics with organic electronics and
photocells, etc. onto flexible plastic substrates (Williams) Nanoscale optical sensing and nano-antennas (Drew)
Fuhrer Group - Electronic Properties Fuhrer Group - Electronic Properties of Carbon Nanotubes of Carbon Nanotubes
1 10104
105
(c
m2 /V
s)
Vth - V
g (V)
50 K 100 K 150 K 200 K 250 K 300 K
Ultra-long nanotubes:• Charge carrier mobility (highest of any semiconductor at RT)• Saturation velocity
Nanotube transistors: • Single-electron detection and memory• High-frequency devices
Novel Imaging/Fabrication Techniques:• Scanning-Probe microscopies of transport
Collaborations:• John Melngailis (ECE) – electron microscopy, electron-beam deposition of metal contacts• Gary Rubloff (Materials) – ALD of metals, high-k dielectrics on nanotubes
Funding: NSF, Army Research Lab, Northrop-Grumman T. Dürkop, et al., Nano Letters 4, 2004
Fuhrer Group - Molecular ElectronicsFuhrer Group - Molecular Electronics• Single-molecule measurements in electromigration-fabricated break junctions• First observation of expected signatures of resonant conduction through a single molecular state: Lorentzian resonance with conductance ~G0.
Collaboration with Larry Sita (Chemistry), Harold Baranger, Weitao Yang (Duke University)
Funding: NSF, DOE
-100 -50 0 50 1000.0
0.2
0.4
0.6 Experiment
G (
GO =
2e2 /h
)
V (mV)
2-Lorentzian fit
S. A. Getty, et al., (submitted to PRL)http://xxx.lanl.gov/abs/cond-mat/0409433
Fuhrer Group - Other Research Fuhrer Group - Other Research
“Nanopatches”: Two-dimensional crystals of layered transition-metal dichalcogenides
Collaboration with Ellen Williams (Physics)Funding: NSF
Thin-film electronics with nanostructured organic materials or carbon nanotube films
Collaboration with Ellen Williams (Physics), Sang Bok Lee (Chemistry), Romel Gomez (ECE)Funding: LPS Au
Au
Nanotube film bare
SiO2
TaS2 Nanopatch with gold electrodes
Nanotube Thin-Film Transistor
Laboratory for NanoSpintronicsPI: Min Ouyang
(http://www2.physics.umd.edu/~mouyang/)
Research Interest:(1) Development of novel synthetic methodologies for low dimensional
spin-based hybrid organic-inorganic nanostructures.
NW-NT heterojunction
Nature 399, 48 (1999) Carbon SWNT
Science 292, 650 (2001) CdSe Quantum Dots
Science 301, 580 (2003)
5nm1nm50nm
(2) Investigation of fundamental basis for spin-charge interactions and spin transport within nanostructured systems with new experimental techniques such as femtosecond optical spectroscopy, magnetotransport and low temperature scanning probe microscopy.
Time resolved Faraday rotation spectroscopy for investigating spin dependent physics in nanostructures
Science 301, 580 (2003)
Williams group - statistical mechanics Williams group - statistical mechanics of surface structuresof surface structures
Application of direct imaging techniques to determine structural distributions:
• equilibrium statistical mechanics•Step free energies•Fluctuation time constants•Size-dependent crossover
Nanostructure Evolution: • Predictive evolution based on step unit • Driven Instabilities and patterning
Stochastic “predictability”:• Demonstration of first passage phenomena
Collaborations:• Theory: Einstein, Weeks, DasSarma
Funding: NSF, DOE
Williams Group - Electromigration and NoiseWilliams Group - Electromigration and Noise
Fundamental issues of diffusional bias due to
electron scattering from internal surfaces • pattern formation - kinetic instabilities• direct observations of fluctuation bias
Instrumental/Materials applications: • Development of MFM to observe current crowding directly•Development of UHV nanowire fabrication
Correlation of electron transport noise with atomic scale structure
Collaborations:• Theory: Philip Rous, UMBC•Experiment: M. Fuhrer, S.B. Lee (Chemistry
Funding: NSF, DOE
Williams group - organic electronics Williams group - organic electronics
Investigation of interface effects as scale thickness and lateral scale of organic device structures
•Organic MBE•Nano-transfer print lithography
Thin-film electronics with nanostructured organic materials or carbon nanotube films
Collaboration with M. Fuhrer (Physics), Janice Reutt-Robey, Sang Bok Lee and Phil DeShong (Chemistry), Danilo Romero (ECE)Funding: LPS
1.6 1.8 2 2.2 2.4 2.6 2.8
10 100
368
372
376ZnCr
2O
4
0 (c
m-1)
Temperature (K)
The magnetic frustration of Cr ions in corner sharing tetrahedra (the pyrochlore lattice) have leads to a Neel temperature of 12 K despite a Curie-Weise temperature of 390 K. The frustration is broken by a Peierls distortion of the lattice at TN and a triply degenerate IR phonon splits into a singlet and doublet. Softening of the phonon above TN probe spin correlations in the spin liquid state. Sushkov et al., PRL accepted
Drew Group: Oxide Magnetism
Probing spin correlations with IR phonons in the strongly frustrated magnet ZnCr2O4
Collaborations: MRSEC, CSR, Materials, Cheong (Rutgers), Lynn (NIST).Funding: NSF MRSEC
Drew Group: High TC Superconductivity
1H H
H i
ARPES: Nd2-xCexCuO4
Armitage, et al.,PRL 87, (2001).
Rapid growth of H observed in pseudogap state is signature of Fermi pockets. Stripes, “arcs”, Mott transition and other models lead to reduction of H
Fermi pockets in underdoped YBa2Cu3O6+x deduced from measurements of the Hall effect in the infrared.
L. Rigal et al., PRL 93 (2004).
Collaborations: Greene (CSR), Gu (Brookhaven), Millis (Columbia). Funding: NSF
20 40 60 80 100 120 140 1601E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
Far Field Throughput of NSOM Probes
Th
rou
gh
pu
t
Minor Axis of Aperture (nm)
Etched tip Etched tip Pulled tipE
E
E
20 40 60 80 100 120 140 1601E-8
1E-7
1E-6
1E-5
1E-4
1E-3
0.01
0.1
1
Far Field Throughput of NSOM Probes
Th
rou
gh
pu
t
Minor Axis of Aperture (nm)
Etched tip Etched tip Pulled tipE
E
E
E
E
E
Drew Group: Nano-optics High optical throughput NSOM probes have been realized using etched polarization preserving fiber.
Applications: florescence imaging, quantum dot spectroscopy, direct writing superconducting circuits.
Collaborations: LPS, Materials, Williams, Phaneuf. Funding: LPS
Diluted Magnetic SemiconductorsA1-xMxB
Examples: Hg1-xMnxTe, Pb1-xGdxTe, Ga1-xMnxAsProperties: 1. Electronic properties influence magnetic
properties and vice versa. 2. Large negative magnetoresistance.
3. Controllable bandgaps.Applications: 1. Frequency tunable IR detectors.
2. Avalanche photodiode detectors. 3. Thermoelectric components. 4. Magnetic field detectors.
Research Projects: 1. Magnetic contribution to heat capacity. Probe of exchange interactions.
2. MBE-prepared thermoelectric materials.
3. Magnetically tunable IR detectors.Collaborations: Institute of Physics (Warsaw), CSR, LPS,
Notre Dame, UMES, Howard U.
Anderson group
Quantum Computing*
Josephson Junction Qubits
Rabi Oscillations in an LJ isolated junction
0 10 20 300.0
0.2
0.4
0.6
Time (ns)
P1
LJJJ-Nb
7.6 GHz
|0>|1>
Coherence time:T2
' ~10 ns ~ 1/1
7.6 GHz Microwaves switched on at t=0 when resonant with 0->1 transition
1o
•Present Research: Microwave spectroscopy in coupled Josephson
junctions. Investigation of escape rates, isolation schemes and variable
coupling approaches. Examine gate operations. Prepare 10-qubit chips.•Collaborators: CSR, Wellstood, Lobb, Dragt•Funding: LPS
Bhagat Group
Ferromagnetic Resonance has been the main focus of the Bhagat group. We began work with single crystals (pure metals & alloys), branched into amorphous alloys (metglasses) and disordered FM’s (…etc), perovskite manganites, Garnets, orthoferrites, and most recently we are concentrating in microwires and nanostructural materials- powders, thin films, multi-layers.
Collaborations: groups in Russia and Spain, S. Lofland (Rowan University) and S. Tyagi (Drexel).
Condensed Matter at Laboratory for Physical Sciences
Bruce Kane (Visiting Associate Research Scientist
Semiconductor base quantum computer
Keith Schwab (Adjunct Assistant Professor)
Superconductor based quantum computer, Low temperature physics
Barry Barker
low temperature STM
SET Array for QCBruce Kane, LPS
• Array of Al SETs separately addressable using scanned probe
• Randomly doped Si substrate: weak localization measurement of P -doped layer to measure dopant segregation and diffusion
• Application: Spin Quantum Computing in Si
Quantum Properties at the Nanoscale
• Quantum Limits of Motion in Nanomechanics – K. Schwab - LPS
• Demonstrate the quantum behavior of a nanomechanical oscillator at 10mK temperatures.
• Show the effects of the uncertainty principle, quantized energy, and the existence of superposition
• Nanoscale Landscape of Semiconductor Dopants – B.I. Barker - LPS
• Probe spatial extent, spectroscopic features and Zeeman splitting of dopants in semiconductors
• Develop Very-Low Temperature STM for spectroscopic measurment of Zeeeman splitting - test Te/GaAsy.)
rf SET10 MHZ resonator
Condensed Matter Experiment• Limiting Issues
Quality/Quantity of space issues Area and quality of laboratory space and space for equipment
storage, poor AC and electrical power. Office space for Post-docs, Grad students Poor facilities support: no clear administrative process to
initiate laboratory modifications, no recognizable tracking system once process is initiated, PIs waste huge amounts of time dealing with even trivial facilities issues that will be fully paid by grants. Research activities can be delayed for years. Major efforts by outstanding Associate Chair cannot solve problem.
Bureaucratic Hurdles University safety officials are helpful within their limits, but
unaware of state-of-the art approaches to safe laboratory practices. Individual faculty member must research any new safety issue on his/her own time, and then spend large effort to convince safety staff that modern approaches are viable. (And then deal with facilities…)
…continued
Condensed Matter Experiment• Limiting Issues
Bureaucratic Hurdles (continued) Limited U. support for activities required/encouraged by funding
agencies: educational outreach, industrial outreach, recruiting and supporting diverse population of graduate students, outreach to developing countries
Research scientist ranks in CMPS barred to laboratory managers even where Ph.D. level expertise is required
Repetitive wasteful paperwork/reporting burdens Research Environment/Intellectual Environment
U. administration slow to recognize (and support faculty in responding to) national science initiatives and directions (e.g. nanoscience, advent of DHS…). Administratively determined priorities and plans poorly communicated to faculty.
Multiplication of initiatives, centers, etc. fragments intellectual community. Specific to CM - need to coordinate Biophysics, Nanoscience in CM, IREAP, MCINSE efforts to consolidate intellectual community