Carlos J. Arguello

Department of Physics, Columbia University

538 W 120TH ST, New York, NY 10027

1309 Pupin Hall

email: carlosj@phys.columbia.edu

 

About Me:

I´m currently a 7th year Physics Ph.D. candidate at Columbia University. I’m working under the direction of Professors Yasutomo Uemura and Abhay Pasupathy, on condensed matter physics and being supported by NSF through a PIRE grant to study unconventional superconductivity using two techniques: muSR (muon spin rotation) and STM (Scanning Tunneling Microscopy).


From the computational side, I have experience on ab-initio (DFT) calculations using VASP, LMTART and Quantum Espresso. In spite the inherent limitations of LDA to treat strongly correlated systems, from a qualitative point of view they’re useful. I use Python scripts to extract the relevant information from the calculations as needed.


Before joining Prof. Pasupathy's and Prof. Uemura's groups, I used DFT to understand its limitations for strongly correlated systems, and tried to adapt simple Hubbard and then more elaborated Anderson models to these systems in order to predict some of their thermodinamical quantities. It turned out to be very difficult to do, but gave me a great deal of experience using Python along with the scientific library scipy.


Next is a summary of my Ph.D work:


STM measurements in dichalcogenides and pnictides (with Prof. Abhay Pasupathy).


My main focus is to understand exotic electronic phases in strong correlated materials. In particular during my time in the group I have studied charge ordered phases in dichalcogenides. I also have taken part in studies involving pnictides and Mott insulators.


I use MATLAB for image processing, particulary Fourier analysis and noise filtering. I also perform DFT calculations and mathematical modeling, for comparisons with the experimental data obtained. I use the open source code Quantum-Espresso (DFT) and Python to manipulate the output files and extract the relevant information.


From the instrumentation side, my research work with professor Pasupathy has included the development and maintenance of a variable temperature UHV STM. This includes working with with Ultra High Vacuum systems (UHV), cryogenic systems, and electronic and control systems. I have also used CAD tools (SolidWorks) for design and modification of several components.


Studies of magnetic and superconducting materials using Muon Spin Rotation (with Prof. Yasutomo Uemura).


I have done Muon Spin Rotation research mostly at TRIUMF (Vancouver, Canada), but I have also done part of my research in the Paul Schreder Institute (Switzerland) and in ISIS (UK). By using a beam of spin polarized muons and taking advantage of the dipolar coupling of spin and magnetic fields, we probe exotic spin configurations (spin ice, spin glass systems), superfluid density in several underdoped/doped superconductor and heavy fermions, as well as coexistence of superconductivity and magnetic order in different systems. My current focus is on doping substitutions in high Tc superconductors, as well as coexistence of magnetism and superconductivity in doped 122 systems.


Data analysis precess involves fitting to the experimental data known functional forms applicable to different magnetic configurations. It has also included implementing Monte Carlo numerical simulations of MuSR lineshapes for different static and dynamic magnetic configurations (using C++ and Python).


My publication list is on my CV.

My Curriculum Vitae: CV_CarlosJ_Arguello.pdf