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Search Publications by: Nikolai Klimov ()

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Displaying 26 - 49 of 49

Coulomb drag and counterflow Seebeck coefficient in bilayer-graphene double layers

July 21, 2017
Author(s)
Jiuning Hu, David B. Newell, Jifa Tian, Nikolai N. Klimov, Tailung Wu, Yong Chen
We have fabricated bilayer-graphene double layers separated by a thin (~20 nm) boron nitride layer and performed Coulomb drag and counterflow thermoelectric transport measurements. The measured Coulomb drag resistivity is nearly three orders smaller in

Impact of Varying Vacuum Levels on Self-Heating in Photonic Thermometers

July 1, 2017
Author(s)
Zeeshan Ahmed, Nikolai N. Klimov, James R. Hands, James A. Fedchak
Here we examine the impact of vacuum levels on self-heating in photonic crystal cavity thermometers. Our results suggest that background gas pressure has a negligible impact on self- heating correction to the temperature-wavelength calibration.

Optomechanical Quantum Correlations

May 18, 2017
Author(s)
Thomas P. Purdy, Karen E. Grutter, Kartik A. Srinivasan, Nikolai N. Klimov, Zeeshan Ahmed, Jacob M. Taylor
We present methods to measure optical quantum correlations arising from an optomechanical interaction even when large classical noise sources are present. We demonstrate quantum- backaction-noise-calibrated Brownian motion thermometry as a metrological

Chip-Packaged Silicon Photonic Nanoscale Thermometers

November 30, 2016
Author(s)
Nikolai Klimov, Thomas P. Purdy, Zeeshan Ahmed
We report on the development of on-chip integrated packaged nanoscale silicon photonic themperature sensors capable to detect temperature difference as small as 70 µK, thus showing the potential to replace legacy-based resistance thermometers

Ring Resonator Thermometry

October 31, 2016
Author(s)
Nikolai Klimov, Zeeshan Ahmed
We report on our study of a temperature response of ring resonator based sensors and their interchangeability over a wide temperature range. Our results suggest that with a proper fabrication process control the interchangeability in photonic thermometers

Gas Uptake of 3-D Printed Acrylonitrile Butadiene Styrene (ABS) Using a Vacuum Apparatus Designed for Absorption and Desorption Studies

October 25, 2016
Author(s)
Makfir Sefa, Zeeshan Ahmed, James A. Fedchak, Nikolai Klimov, Julia Scherschligt
We describe a vacuum apparatus for determining the outgassing rate into vacuum, the diffusion coefficient, and the amount of gas absorbed for various materials. The diffusion coefficient is determined from a model applied to time-dependent desorption data

Thermometry with Optomechanical Cavities

June 6, 2016
Author(s)
Thomas P. Purdy, Karen E. Grutter, Kartik Srinivasan, Nikolai Klimov, Zeeshan Ahmed, Jacob Taylor
Thermally-driven motion of a nanomechanical resonator may be employed as an absolute thermometer. We experimentally measure radiation pressure shot noise induced quantum correlations to absolutely calibrate the motional signal transduced onto an optical

Edge-state Transport in Graphene p-n Junctions in the Quantum Hall Regime

December 7, 2015
Author(s)
Nikolai Klimov, Son T. Le, Jun Yan, Pratik Agnihotri, Everett Comfort, Ji Ung Lee, David B. Newell, Curt A. Richter
We experimentally investigate charge carrier transport in a graphene p-n junction device by using independent p-type and n-type electrostatic gating which allow full characterization of the junction interface in the quantum Hall regime covering a wide

On-Chip Integrated Silicon Photonic Thermometers

September 1, 2015
Author(s)
Nikolai N. Klimov, Thomas P. Purdy, Zeeshan Ahmed
The fundamental limitations of resistance-based thermometry and the desire to reduce sensor ownership have produced considerable interest in the development of photonics-based temperature sensors as an alternative to resistance thermometers. Photonic

Towards Reproducible Ring Resonator Based Temperature Sensors

September 1, 2015
Author(s)
Nikolai Klimov, Michaela Berger, Zeeshan Ahmed
In recent years photonic devices have emerged as a powerful tool for developing novel, high-sensitivity sensors. In particular, tremendous progress has been reported in developing photonic temperature sensors using a wide variety of materials including

On-Chip Silicon Waveguide Bragg Grating Photonic Temperature Sensor

August 4, 2015
Author(s)
Nikolai Klimov, Sunil Mittal, Zeeshan Ahmed, Michaela Berger
Resistance thermometry is a time-tested method for temperature measurements. Fundamental limits to resistance-based approaches, spurred our interest in developing photonic temperature sensors as a viable alternative. In this study we demonstrate that our

Pseudomagnetic Fields in a Locally Strained Graphene Drumhead

August 25, 2014
Author(s)
Shuze Zhu, Yinjun Huang, Nikolai Klimov, David B. Newell, Nikolai Zhitenev, Joseph A. Stroscio, Santiago D. Solares Rivera, Teng Li
Recent experiments reveal that a scanning tunneling microscopy (STM) probe tip can generate a highly localized strain field in a graphene drumhead, which in turn leads to pseudomagnetic fields in the graphene that can spatially confine graphene charge

Electro-Mechanical Properties of Graphene Drumheads

June 22, 2012
Author(s)
Nikolai N. Klimov, Suyong S. Jung, Shuze Zhu, Teng Li, C. Alan Wright, Santiago Solares, David B. Newell, Nikolai B. Zhitenev, Joseph A. Stroscio
The electro-mechanical properties of a suspended graphene layer are determined by scanning tunneling microscopy (STM) and spectroscopy (STS) measurements and computational simulations of the graphene membrane mechanics and morphology. The graphene membrane

Characteristics of Graphene for Quantized Hall Effect Measurements

June 1, 2012
Author(s)
Randolph E. Elmquist, Mariano A. Real, Irene G. Calizo, Brian G. Bush, Tian T. Shen, Nikolai N. Klimov, David B. Newell, Angela R. Hight Walker, Randall M. Feenstra
This paper describes concepts and measurement techniques necessary for characterization of graphene in the development of graphene-based quantized Hall effect (QHE) devices and resistance standards. We briefly contrast the properties of graphene produced

Mechanism for puddle formation in graphene

December 5, 2011
Author(s)
Shaffique Adam, Suyong S. Jung, Nikolai N. Klimov, Nikolai B. Zhitenev, Joseph A. Stroscio, Mark D. Stiles
Close to charge neutrality, graphene's energy landscape is highly inhomogeneous, forming a sea of electron-like and hole-like puddles that determine the properties of graphene at low carrier density. However, the details of puddle formation have remained

Microscopic Polarization in the Bilayer Graphene

April 24, 2011
Author(s)
Joseph A. Stroscio, Suyong S. Jung, Nikolai N. Klimov, David B. Newell, Nikolai B. Zhitenev, Gregory Rutter
Bilayer graphene has drawn significant attention due to the opening of a band gap in its low energy electronic spectrum, which offers a route to electronic applications that is not practical with single layer graphene. The gap can be either tunable through

Evolution of Microscopic Localization in Graphene in a Magnetic Field: From Scattering Resonances to Quantum Dots.

January 9, 2011
Author(s)
Suyong S. Jung, Gregory M. Rutter, Nikolai Klimov, David B. Newell, Irene G. Calizo, Angela R. Hight Walker, Nikolai Zhitenev, Joseph A. Stroscio
Graphene is a unique material displaying high-mobility transport in monolayer-thin films. However, its properties are strongly dependent on interactions with substrates, local charges and environment. Scanned probe microscopies can be used to locally probe