ISSP Stay report of Prof. BARRAZA- LOPEZ, Salvador
Salvador Barraza-Lopez
University of Arkansas
The main outcome from my visit to the ISSP was advancing a computational tool for calculating second-harmonic generation (SHG) in collaboration with Professor Taisuke Ozaki. Said tool expands wave-functions on a basis set of localized atomic orbitals (which are available in OpenMX ), and it was developed by Angiolo Huaman and Luis Enrique Rosas at my research group.
The effort was supported from the beginning: Professor Ozaki has developed this functionality on OpenMX and was extremely kind to share unpublished results, which gave us both a benchmark and an expectation of how our results should look like. Angiolo, Luis Enrique and I used most of Fall 2026 improving the methodology (which included basic methodological changes as well as the creation of a single parallel code) and rewriting a manuscript. I parallelized and streamlined our code while at the ISSP, and Luis Enrique successfully cleared bugs in the last parts of it. Details of a proof-of-principle code were published in early 2026 (Huamán et al., J. Phys.: Condens. Matter 38, 045901 (2026)). Other additions are being coded, and we intend to continue this collaboration as I return to America.
During my time at the ISSP, I was also able to further collaborations with experimental groups at Arkansas (arXiv:2602.03996), Wisconsin (arXiv:2510.03220), Germany and China (Chang et al., Nat. Commun. 16, 11063 (2025); Ji et al., Adv. Funct. Mater. e24380 (early view, 2026)). Professor Ozaki also supported a visit by experimental collaborator Kai Chang in early November of 2025; the visit was critical to finalize three papers and set directions for further collaboration. Most especially, Professor Ozaki also allowed me to bring PhD student Luis Enrique Rosas to Japan for a three-week stay with the purpose of finalizing significant details of our code (Luis Enrique sits at the lower left in the picture). I will always cherish Professor Ozaki’s generosity.
The stay at Tokyo also brought a chance to present my research and to attend some of the multiple colloquia and events; the number of international visitors is a remarkable sign of the Institute’s stature and intellectual prowess.
I wish to close this report expressing my gratitude to additional people who helped make this stay memorable: Yuko-san (International Liason Office), Eguchi-san, Dr. Swati Chaudhary, and Dr. Armando Pezo. I also thank Professors Fukuda, Oka, Tsunesugu, and Tiantian Zhang for multiple exchanges during my visit. Last but not least, I shall thank Dr. Babu Prasad at Professor Ozaki’s group, whose easy smile and helpfulness were remarkable as well.
There are multiple fond memories from my time at the ISSP, and I look forward to the possibility of coming back.