POSTPONED: Electron Dynamics in Materials from First Principles

Who: Marco Bernardi, CalTech
Tuesday, March 24, 2020 - 4:00pm
321 Allen Hall

Recent progress in combining density functional theory and related methods with the Boltzmann transport equation are enabling spectacular advances in computing electron dynamics in materials from first principles. The interaction between electrons and lattice vibrations (phonons) plays a central role as it governs carrier dynamics near room temperature and at low energy. I will present our recently developed methods to compute electron-phonon scattering processes from first principles, and show how these advances enable calculations of electron dynamics in materials, including: 1) First-principles calculations of the carrier mobility, leading to new insight into the mechanisms governing charge transport in semiconductors [1,2] and oxides [3,4]. We will focus on charge transport in SrTiO3 and discuss an approach to compute the electron spectral function and transport in the polaron regime. In SrTiO3, our results show that the strong e-ph interactions lead to a quantum transport regime beyond the quasiparticle scattering paradigm, in which the electron scattering rate violates the Planckian limit. Very recent results for Sr2RuO4 and thermoelectricity in SrTiO3 will also be discussed. 2) Precise calculations of electron spin relaxation times in semiconductors, using a new approach to compute and analyze spin-phonon interactions [5]. Application of this framework to spin qubits will be examined. We will also introduce a method for computing electron-defect (e-d) scattering [6] and defect-limited transport from first principles, and discuss its potential application to topological materials. Also outlined will be our efforts to develop an open source code, called PERTURBO [7], to make these new computational methods and workflows available to the community.

[1] J.-J. Zhou and M. Bernardi Phys. Rev. B (Rapid Commun.) 94, 201201 (2016)
[2] N.-E. Lee, J.-J. Zhou, L. Agapito and M. Bernardi Phys. Rev. B 97, 115203 (2018)
[3] J.-J. Zhou, O. Hellman and M. Bernardi Phys. Rev. Lett. 121, 226603 (2018)
[4] J.-J. Zhou and M. Bernardi Phys. Rev. Research 1, 033138 (2019)
[5] J. Park, J.-J. Zhou and M. Bernardi Phys. Rev. B 101, 045202 (2020)
[6] I.-T. Lu, J.-J. Zhou and M. Bernardi Phys. Rev. Mater. 3, 033804 (2019)
[7] J.-J. Zhou, J. Park, I.-T. Lu, I. Maliyov and M. Bernardi arXiv 2002.02045