Steve Byrnes's Homepage

I'm currently a graduate student at UC Berkeley, working towards a Ph.D. in Physics. I'm working in this research group. (Before that, I worked in this one and this one.) I graduated from Harvard University in June 2007, earning a B.A. summa cum laude in Physics and Math.

My email address is .

Links to things I've written:

Things to make life easier for scientists:

HERE is a study sheet for the Physics GRE which I put together in college. The file (an older version) is also hosted here.

HERE is a Mathematica package I wrote to deal with units and dimensional analysis in Mathematica. It works differently than Mathematica's built-in units package--unlike the built-in package, it works smoothly with Mathematica's numerical operations (e.g., "NIntegrate", "FindRoot"). Click the link and open the notebook in Mathematica for information on how to install and use it.

HERE is a Mathematica program I wrote that solves the Fresnel equations to calculate transmission and reflection from multilayer thin films. It also calculates the Poynting vector and the absorbed energy density as a function of depth. Click the link and open the notebook in Mathematica to read how to use it. If you're curious but do not have Mathematica, here is my source code. (Warning: This was written in Mathematica Version 6. I've been told it doesn't run in version 4.1. If this program doesn't work for you, there are similar ones elsewhere: 1, 2, 3, 4.)

HERE is my guide to the confusing and inconsistent way that the terms "fermi level", "fermi energy", "electrochemical potential", "chemical potential", and related terminologies are used in different fields of physics and chemistry.

HERE is my guide to installing the LAMMPS molecular-dynamics simulation software in Windows (through cygwin), written for people who have never used UNIX before.

Peer-reviewed publications: (email me for a PDF)

S.Y. Yang, J. Seidel, S.J. Byrnes, P. Shafer, C.-H. Yang, M.D. Rossell, P. Yu, Y.-H. Chu, J.F. Scott, J.W. Ager III, L.W. Martin, R. Ramesh, "Above-bandgap voltages from ferroelectric photovoltaic devices." Nature Nanotechnology 5, 143 (2010). See also: Article summary in Nature Physics "Research Highlights", Article summary in Nature Photonics "News and Views".

S.Y. Yang, L.W. Martin, S.J. Byrnes, T.E. Conry, S.R. Basu, D. Paran, L. Reichertz, J. Ihlefeld, C. Adamo, A. Melville, Y.-H. Chu, C.-H. Yang, J.L. Musfeldt, D.G. Schlom, J.W. Ager III, R. Ramesh, "Photovoltaic effects in BiFeO₃." Appl. Phys. Lett., 95, 062909 (2009).

E.E. Sigmund, H. Cho, P. Chen, S. Byrnes, Y.-Q. Song, X.E. Gu, T.R. Brown, "Diffusion-based MR methods for bone structure and evolution." Mag. Res. Med. 59, 28 (2008).

S. Byrnes, "Poset Game Periodicity." INTEGERS: Electronic Journal OF Combinatorial Number Theory 3, G3 (2003).

Term papers from grad school:

HERE is an introduction to Schottky barrier (and "MIS-IL") solar cells, a type of solar cell commonly used in laboratory studies but not commercially viable today. I wrote it for a Berkeley course on the physics of solar cells ("NSE 290").

HERE is a paper proposing and discussing the idea of facilitating lasing in silicon (or other "indirect-bandgap" materials) by "phonon pumping"--i.e., trying to set up stimulated emission of phonons and photons simultaneously, instead of just photons as in a normal laser. I found that my idea, although intuitively appealing, does not work. I wrote this paper for a Berkeley course on AMO physics ("Physics 238").

HERE is a brief introduction to "polarons", a concept in solid-state physics. I wrote it for a Berkeley course on semiconductor materials ("MSE 223").

Some math papers from high school and college:

HERE is where you can find information on "Poset Game Periodicity", a prize-winning math paper I wrote in high school.

HERE is a paper on the representation theory of, first, the symmetric groups (aka permutation groups) and second, the family of Lie algebras which physicists call SU(N) and mathematicians call SL(N). I wrote it for a Harvard math course on abstract algebra ("Math 250"). I chose the topic because of its relevance to particle physics.

HERE is a paper on the "Number Field Sieve" prime-factoring algorithm, which I wrote for another Harvard math course on abstract algebra ("Math 129"). The file is also hosted here.

Hobbies and other things:

HERE are some notes I wrote up about a run-in I had with repetitive strain injury.

HERE is a list of my contributions to Wikipedia :-)

HERE is a little javascript stopwatch I made.