Kevin M. Ryan; Carlos G. Torres-Castanedo; Dominic P. Goronzy; David A. Garcia Wetter; Matthew J Reagor; Mark Field; Cameron J Kopas; Jayss Marshall; Michael J. Bedzyk; Mark C. Hersam; Venkat Chandrasekhar
Characterization of Nb films for superconducting qubits using phase boundary measurements Journal Article
In: Applied Physics Letters, vol. 121, pp. 202601, 2022.
Abstract | Links | BibTeX | Tags: epitaxial, instrumentation, Superconductivity, superconductor
@article{Ryan2022,
title = {Characterization of Nb films for superconducting qubits using phase boundary measurements},
author = {Kevin M. Ryan and Carlos G. Torres-Castanedo and Dominic P. Goronzy and David A. Garcia Wetter and Matthew J Reagor and Mark Field and Cameron J Kopas and Jayss Marshall and Michael J. Bedzyk and Mark C. Hersam and Venkat Chandrasekhar},
url = {https://arxiv.org/abs/2207.13125
https://aip.scitation.org/doi/10.1063/5.0119932},
year = {2022},
date = {2022-07-26},
urldate = {2022-07-26},
journal = {Applied Physics Letters},
volume = {121},
pages = {202601},
abstract = {Continued advances in superconducting qubit performance require more detailed understandings of the many sources of decoherence. Within these devices, two-level systems arise due to defects, interfaces, and grain boundaries, and are thought to be a major source of qubit decoherence at millikelvin temperatures. In addition to Al, Nb is a commonly used metalization layer for superconducting qubits. Consequently, a significant effort is required to develop and qualify processes that mitigate defects in Nb films. As the fabrication of complete superconducting qubits and their characterization at millikelvin temperatures is a time and resource intensive process, it is desirable to have measurement tools that can rapidly characterize the properties of films and evaluate different treatments. Here we show that measurements of the variation of the superconducting critical temperature Tc with an applied external magnetic field H (of the phase boundary Tc−H) performed with very high resolution show features that are directly correlated with the structure of the Nb films. In combination with x-ray diffraction measurements, we show that one can even distinguish variations quality and crystal orientation of the grains in a Nb film by small but reproducible changes in the measured superconducting phase boundary.},
keywords = {epitaxial, instrumentation, Superconductivity, superconductor},
pubstate = {published},
tppubtype = {article}
}
Continued advances in superconducting qubit performance require more detailed understandings of the many sources of decoherence. Within these devices, two-level systems arise due to defects, interfaces, and grain boundaries, and are thought to be a major source of qubit decoherence at millikelvin temperatures. In addition to Al, Nb is a commonly used metalization layer for superconducting qubits. Consequently, a significant effort is required to develop and qualify processes that mitigate defects in Nb films. As the fabrication of complete superconducting qubits and their characterization at millikelvin temperatures is a time and resource intensive process, it is desirable to have measurement tools that can rapidly characterize the properties of films and evaluate different treatments. Here we show that measurements of the variation of the superconducting critical temperature Tc with an applied external magnetic field H (of the phase boundary Tc−H) performed with very high resolution show features that are directly correlated with the structure of the Nb films. In combination with x-ray diffraction measurements, we show that one can even distinguish variations quality and crystal orientation of the grains in a Nb film by small but reproducible changes in the measured superconducting phase boundary.
M. M. Mehta; Venkat Chandrasekhar
A hybrid analog-digital phase-locked loop for frequency mode non-contact scanning probe microscopy Journal Article
In: Review of Scientific Instruments, vol. 85, no. 1, pp. 013707, 2014.
Links | BibTeX | Tags: instrumentation, scanning probe
@article{mehta_hybrid_2014,
title = {A hybrid analog-digital phase-locked loop for frequency mode non-contact scanning probe microscopy},
author = { M. M. Mehta and Venkat Chandrasekhar},
url = {http://scitation.aip.org/content/aip/journal/rsi/85/1/10.1063/1.4862818},
year = {2014},
date = {2014-01-01},
urldate = {2015-10-23},
journal = {Review of Scientific Instruments},
volume = {85},
number = {1},
pages = {013707},
keywords = {instrumentation, scanning probe},
pubstate = {published},
tppubtype = {article}
}
Venkat Chandrasekhar; Manan Mehta
A real-time software simulator for scanning force microscopy Unpublished
2013.
Links | BibTeX | Tags: instrumentation, scanning probe
@unpublished{chandrasekhar_real-time_2013,
title = {A real-time software simulator for scanning force microscopy},
author = { Venkat Chandrasekhar and Manan Mehta},
url = {https://arxiv.org/abs/1307.7679},
year = {2013},
date = {2013-01-01},
urldate = {2016-12-28},
keywords = {instrumentation, scanning probe},
pubstate = {published},
tppubtype = {unpublished}
}
Venkat Chandrasekhar; M. M. Mehta
RTSPM: Real-time Linux control software for scanning probe microscopy Journal Article
In: Review of Scientific Instruments, vol. 84, no. 1, pp. 013705, 2013.
Links | BibTeX | Tags: instrumentation, scanning probe
@article{chandrasekhar_rtspm:_2013,
title = {RTSPM: Real-time Linux control software for scanning probe microscopy},
author = { Venkat Chandrasekhar and M. M. Mehta},
url = {http://scitation.aip.org/content/aip/journal/rsi/84/1/10.1063/1.4775717},
year = {2013},
date = {2013-01-01},
urldate = {2015-10-21},
journal = {Review of Scientific Instruments},
volume = {84},
number = {1},
pages = {013705},
keywords = {instrumentation, scanning probe},
pubstate = {published},
tppubtype = {article}
}
