Northwestern University
Internal competition for limited submission to NSF Major Research Instrumentation Program (MRI-R2)
Instrument Development:
Nanoscale Spatial Microwave Characterization at Variable Temperatures and
Magnetic Fields
Vita or Biosketch (1-4 pages) for PI and all co-Is
Description of the equipment and need justification (1-2 page)
1. Description of the equipment and need justification
The goal of the project is to create a new facility for fundamental measurements needed for discovery
of new physical principals and prototyping of new generation of electronic devices which could replace
existing semiconductor and magnetic technologies in a decade or so. Our expertise in a scanning probe
microscopy, materials characterization, low temperature measurements, radiofrequency (RF) and
microwave (MW) measurements, optics, clean room micro fabrication, cryogenic engineering, as well as
collaboration with other projects, will help us to develop a new instrumentation for quantitative
measurements and imaging of electromagnetic field components, materials characterization, electrical and
magnetic devices of micro- and nano- scale by establishing spatially resolved waveform and frequencydomain techniques unavailable at the Northwestern University. In addition to the PI and co-PIs directly
involved in the project, the instrument is expected to benefit research programs in a number of
departments across the Northwestern.
1.1. Description of the equipment/facility
The proposed system will consist of: (1) high-frequency equipment; (2) custom developed scanning
probe microscopy platform (hardware, electronics, and software); (3) custom developed sample pucks; (4)
a variable temperature cryostat; (5) a variable high magnetic fields.
Major concept of the equipment/facility: The facility will provide a unique combination of
experimental conditions and modularity for multiple projects. Our goal is to achieve flexibility without
sacrificing the performance of each module. Following this approach, different modules may be added at
any time depending on the availability of funding and users’ interest.
(1) High-frequency equipment (1MHz-50GHz range): 1. Network Analyzer. The availability of a
network analyzer is critical for the characterization of microwave circuits in any experiment involving
high frequencies. 2. Signal Generator is critical for frequency modulation, pulse generation and other
signal modulation techniques. 3. Spectrum Analyzer. For detailed analysis of signals, a spectrum
analyzer is extremely useful, and provides capabilities not available with only a network analyzer. 4.
High Frequency Oscilloscope. For some of the experiments the ability to visualize the real-time behavior
of the signals coming from the devices is critical. A multi-channel oscilloscope would also enable us to
make direct measurements of noise (both autocorrelation and cross-correlation).
(2) Scanning probe microscope (hardware, electronics, and software): Hardware: We have already
built and tested low temperature scanning probe microscope (SPM) based on compact linear piezo stages
made by Attocube and force sensors based on tuning fork transducer. We will design (in collaboration
with C. Liu/ME and P. Kabos/NIST) special probes for the spatial and spectral bandwidth MW near-field
measurements and imaging. Controllers – We have most of the controllers available, some will be
custom made. Software – We have a combination of commercial open platform and custom built
software. Additional custom components will also be made.
(3) Custom sample pucks with multiple electrical leads for sample connections, with integrated heater
and thermometer, and passive thermal expansion compensation layout will be designed, and made.
(4) Variable temperature cryostat: The primary microscope platforms will be based on XXX
(Venkat?) dip-stick setups. Each dip-stick will be inserted into the magnet system. These will cover a
wide range of temperatures from 20 mK up to 400 K by simply changing the dip-stick.
(5) Superconducting Magnets: Venkat?
1.2. Need justification
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Northwestern University
Internal competition for limited submission to NSF Major Research Instrumentation Program (MRI-R2)
The ability to probe local electrical impedance quantitatively opens up a wide range of applications
for this technology. Its quantity is a complex number with strong frequency dependence. For
electronic applications, the lower range microwave frequencies (GHz) are the most relevant and
best suited to characterize the electrical impedance of materials. A low-temperature version of this
technique is also very useful in studying a wide range of phenomena, including quantum, and
materials, including superconductors, magnetoresistive materials, and others. Unfortunately this
technology is not fully commercialized yet and very rarely available at the central facilities. NIST
(Electromagnetics Division at Boulder) has recently setup a program: “RF Nanoscale and
Molecular Probing Metrology”, which includes radio-frequency and microwave atomic-force
microscope (RF-MW-AFM) development. Dikin already collaborates with them.
This facility will provide a modular, complex platform for long-time experiments that will also
leverage the extensive development and education of new scanning probe microscopy tools and methods
by the co-PIs and other groups at Northwestern. We refer to this as a multi-project instrument with a
variable temperature and magnetic filed SPM, which is entirely absent at the NU, as well as at other
Chicago land facilities like the Center for Nanoscale Materials at the Argonne National Lab.
The focus of this instrument will be a fundamental research and education in nanoscale science and
technology on projects such as the following:
(a) Nanomagnetics (J. Ketterson, V. Chandrasekhar, Physics) Nanosize magnets are essential
constituents of spintronic devices and promise to be used in future magnetic storage elements. While the
static magnetic properties of submicron size ferromagnets have been studied extensively, the highfrequency dynamical properties still remain a subject of intensive investigation. Apart from the potential
commercial interest in making high speed magnetic devices, the fundamental physics of how the size and
shape of a magnetic particle affects its dynamic magnetic properties is also of interest. These dynamic
properties are determined to a great extent by the particle’s spin wave modes.
(b) Luttinger liquids in one-dimensional quantum wires (M. Grayson, EECS) A versatile GHz
microwave experimental system could explore time-of-flight measurements along a Luttinger liquid to
calibrate the interaction constants of these and other one-dimensional systems.
(c) Persistent current in normal metals (V. Chandrasekhar, Physics) Many important questions,
including verification of the expected sign of the persistent current, the temperature dependence of the
amplitude, the effect of electron-electron interactions, can be addressed by precise measurements of the
fractional change in the resonance frequency. For example with a resonant frequency of 6 GHz, the
estimated corresponding frequency shift will be of 36 kHz.
(d) Non-linear optical waveguide devices for nanophotonics (B. Wessels, MSE) In the proposed
research non-linear optical waveguide devices will be developed. Of particular interest are ultra-wideband
thin film electro-optic modulators. This work builds on our recent demonstration of thin film
ferroelectrics with electro-optic coefficients more than an order of magnitude greater than lithium niobate,
the current standard. Thin film strip-loaded waveguide devices will be fabricated for ultra-wideband
frequency operation. Factors limiting bandwidth will be determined through modeling and testing using
the instrumentation requested in this proposal.
(e) Crossed Andreev reflection and elastic co-tunneling (V. Chandrasekhar, Physics) Measuring timedependent correlations between two voltages over a large measurement bandwidth requires sophisticated
high-frequency experimental techniques that are currently unavailable at Northwestern. High-frequency
techniques provide improved signal-to-noise due to the larger measurement bandwidth. In addition, it will
let us perform noise measurements on other systems in which we currently are interested (such as
graphene and single-walled carbon nanotubes), since many of the same experimental tools can be use to
measure noise in these systems at low temperatures.
(f) Nanowires (D. Dikin, ME; H. Espinoza, ME; L. Lauhon, MSE) Carbon nanotubes and Si-based
nanowires are considered as possible option for the next generations of interconnects and highintegration-density structures. Although extensive research is ongoing on the structural, mechanical, and
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Northwestern University
Internal competition for limited submission to NSF Major Research Instrumentation Program (MRI-R2)
optical properties and applications of these materials, very little is known about their behavior in another
important frequency range, from a few megahertz to tens of gigahertz. We are developing non-invasive
measurements technology that allow separating the behavior of the nanostructures of interest from that of
their environment.
(g) Nanocomposites and Metamaterials (D. Dikin, C. Sun, ME) In recent years there have been increased
interest in the development of nanocomposite materials and artificial structures with properties that differ
significantly from the properties of standard materials. Among those are the band-gap materials for
different frequency ranges and the so-called "negative index" materials that support the propagation of
electromagnetic waves with opposite phase and group velocities. Due to their special properties many
challenges in the tailored material design will have to be mastered. With a new instrumentation these
challenges will be possible to address.
A table listing of faculty who will be involved in the submission and the estimated number of
researchers who will benefit from the use of the equipment
2. List of faculty who will be involved in the submission and the estimated number of researchers
who will benefit from the use of the equipment
2.1. A list of faculty who will be involved in the submission
 Venkat Chandrasekhar (Department of Physics & Astronomy)
 Dmitriy Dikin (Department of Mechanical Engineering)
 John Ketterson (Department of Physics & Astronomy)
 Matthew Grayson (Department of Electrical Engineering and Computer Science)
 Chang Liu (Department of Mechanical Engineering)
2.2. The estimated number of researchers who will benefit from the use of the equipment
The following faculty expressed a great interest in the proposed system and may contribute in its
development and future use: Bruce Wessels, Lincoln Lauhon, Mark Hersam, Vinayak Dravid (Material
Science and Engineering). This system might also be of potential interest for: Prem Kumar, Manijeh
Razeghi, Allen Teflove (Electrical Engineering and Computer Science) Scott Barnett (Material Science
and Engineering), Horacio Espinosa and Cheng Sun (Mechanical Engineering), Mercouri Kanatzidis,
Tobin Marks, Chad Mirkin, Michael Wasielewski, and Emily Weiss (Chemistry).
On an annual basis, we estimate that approximately 15 to 20 researchers will benefit from the use of
this system. In addition, a few lab-based courses (surface science, nano science, experimental methods,
etc.) will be prepared based on the development (at the earlier phase) and the operation and maintenance
of this system.
Description of project and management plans, including plans for the maintenance, operation,
and technical support of instrumentation, and for attracting new users (one page);
3. A description of project and management plans, including plans for the maintenance, operation,
and technical support of instrumentation, and a plan for attracting new users
We are going to build an innovative, complex state-of-the-art instrument. The focus of this system is
intensive, long-term fundamental research projects that require continuous use of expensive equipment
and also a development of new educational programs for students with a major in physics, material
science, and engineering.
The instrument will be located in XXX, which is equipped for laboratory services necessary for the
instrument.
Dr. Dmitriy Dikin (Research Assistant Professor with a joint appointment in the Physics and ME
Departments) will be responsible for the construction and detailed technical advice of two graduate
students whose PhD projects will be related to the development of this system. Dikin will also be
responsible for the day-to-day operation of the instrument.
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Northwestern University
Internal competition for limited submission to NSF Major Research Instrumentation Program (MRI-R2)
Dikin has a Master’s degree in cryogenic engineering and electronics, and a PhD in the physics of
superconductivity. He has 20+ years experience in low temperature and high vacuum technologies, 6+
years of experience in nano manipulation, piezo devices, and all types of microscopy. Dikin designed and
constructed a number of devices for experimental low temperature physics, nano mechanics, and high
frequency measurements (see his CV).
3.1. Development plan
The first year of the project will be devoted to careful analysis of the major system components, their
selection and acquisition. At the same time the graduate students and undergraduate students involved
will obtain a background education in: cryogenic technologies, scanning probe microscopy, RF and
microwave measurements, LabView programming, digital signal processing, etc.
The second year of the project will be mostly devoted to engineering, manufacturing and testing of
variable temperatures scanning probe microscope, microwave setup and special evanescent microwave
probes. Team of undergraduate students lead by graduate students and supervised by Dikin. A second
major task for this year will be the installation of major components and their testing.
The third year of the project will be primarily devoted to developing, debugging and testing of the
entire system. At this time we expect to introduce this system to other researchers and students across NU
with the goal to invite a few more active contributors to the development of this complex system tailored
to their own research goals and technical requirements. We also expect to gain the first physical results
for NSF and other agencies’ supported research projects.
3.2. Maintenance, operation, and technical support of the facility
We believe that this complex and modular system can serve as a platform for many years of advanced
research in physics and material science at the nanoscale, as well as becoming an important part of a
broad range of educational programs for Weinberg and McCormick Colleges.
Summary budget.
4. Summary budget
An estimated total budget of $955k for 3 years will be requested to support two graduate students
($40k per person per year or $240k total), one research professor (6 months per year, $180k total), for
purchasing major components (listed below), for materials, fabrication, and testing ($60k total).
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Tentative list of major components of the system, and salaries
High-frequency equipment
Agilent Network Analyzer
Signal Generator
Spectrum Analyzer
Oscilloscope
Scanning probe microscope (components)
Custom sample pucks (components)
Variable temperature cryostat
Superconducting Magnets
Materials, fabrication and testing expanses including cryogenic liquids
Salaries
Total:
Estimated cost, $
455,000
95,000
155,000
85,000
120,000
15,000
5,000
0
0
60,000
420,000
955,000
The cost-sharing commitment of support will be provided by …
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