Personal webpage of Héctor Ochoa
I am an associate research scientist and adjunct professor of Physics at Columbia University.
I work in condensed matter theory.
Here you can find information about my research and other academic activities.
Research interests
Disorder and correlations in low-dimensional systems
Spintronics and magnetism
Graphene and other 2D materials, including moirés
Check out my articles in arXiv.
Selected publications
Degradation of phonons in disordered moiré superlattices, Phys. Rev. Lett. 128, 065901 (2022)
Spintronics in graphene and other two-dimensional materials, Rev. Mod. Phys. 92, 021003 (2020)
Spin hydrodynamics in amorphous magnets, Phys. Rev. B 98, 054424 (2018)
Emergent gauge fields from curvature in single layers of transition-metal dichalcogenides, Phys. Rev. Lett. 118, 026801 (2017)
News
Intrinsic and extrinsic photogalvanic effects in twisted bilayer graphene, posted in arXiv. In this collaboration with Fernando Peñaranda and Fernando de Juan (DIPC), we explore how DC currents produced by shining light on twisted bilayer graphene are not only sensitive to the broken symmetries of the material but to the magic angle itself: the direction of the current is reversed across the magic angle. We also analyzed how the approximate electron-hole symmetry of the model constrains the form of this second-order optical response.
Extended linear-in-T resistivity due to electron-phason scattering in moiré superlattices , in collaboration with Rafael M. Fernandes (U. Minnesota), published in Physical Review B. Here we argue that scattering with soft vibrational modes of a moiré superlattice might explain the observation of a linear-in-T resistivity surviving down to very low temperatures in systems like twisted bilayer graphene.
Electric backaction on moiré mechanics, published in Physical Review B. Here I explore the possibility of controlling the stacking arrangement between two twisted van der Waals layers (such as graphene) by electrostatic means.
For undergrad students: There are research opportunities for you. If you are a student at Columbia and you find some of the stuff in this webpage interesting, shoot me an email to ho2273 at columbia.edu.
Research
I am interested in phenomena at the intersection between hard and soft condensed matter physics, particularly in situations where the floppiness in the structure of the material affects the quantum mechanical behavior of electrons. Examples include electronic membranes such as graphene and other 2D materials, and more recently, the quasi-periodic structures that they form when stacked on top of each other. I am also interested in spin dynamics in solid state, from fundamental phenomena to applications in spintronics.
In the sidebars you can find more information about past and current research projects.
Teaching
I am teaching Introduction to Electromagnetism and Optics (Physics UN1402) this semester. Lectures are on Monday and Wednesday from 1:10pm to 2:25pm. Office hours are on Monday from 2:30pm to 15:30pm and on Friday from 9:00am to 10:00am. My office is 919 CEPSR.