Description of the orbital magnetization in p-wave superconductors on the basis of the modern theory of polarization
Final Report Abstract
Summarizing the presented aspects of my scientific work I believe the scientific freedom related to a postdoctoral fellowship from the Deutsche Forschungsgemeinschaft prepared a solid ground for my future life in academia. I was able to pursue my planned research path which broadened my expertise to superconducting materials. By establishing a sum rule and connecting the optical Hall conductivity to the Berry curvature in the superconducting state I derived the tool kit to address the orbital magnetic moment for these materials as well. I studied the description of the superconducting state exploiting the Bogoliubov-deGennes equation extensively and implemented efficient numerical methods to solve the equations for the gap function self-consistently. The results were used to compute the optical Hall conductivity as functions of the frequency and the temperature. All this helped to understand the underlying mechanism leading to the intrinsic contributions of the Kerr effect. With my work, we could clarify a long lasting discussion on the existence of the intrinsic mechanism in single and multi orbital models. For this understanding my previous work on the normal state Berry curvature was extremely supportive since similar arguments and concepts could be exploited. Including spin-orbit coupling and finite temperatures into the model opens the path for a large number of new effects induced and influences by the superconducting state. In particular, I will focus on the anomalous Nernst effect which is one option to establish the field of spin caloritronics. With this field I will be able to combine my gained knowledge of the description of the superconducting state with my established and broadened expertise in the normal state spintronics and spincaloritronics.
Publications
- Calculating the Berry curvature of Bloch electrons using the KKR method; Phys. Rev. B 84, 075113 (2011)
M. Gradhand, D. V. Fedorov, F. Pientka, P. Zahn, I. Mertig, B.L. Györffy
- Extrinsic spin Nernst effect from first principles; Phys. Rev. Lett. 109; 026601 (2012)
K. Tauber, M. Gradhand, D. V. Fedorov, I. Mertig
(See online at https://doi.org/10.1103/PhysRevLett.109.026601) - First-principle calculations of the Berry curvature of Bloch states for charge and spin transport of electrons; J. Phys. – Cond. Matter 24, 213202 (2012)
M. Gradhand, D.V . Fedorov, F. Pientka, P. Zahn, I. Mertig, B. L. Györff
(See online at https://doi.org/10.1088/0953-8984/24/21/213202) - The Kerr rotation in the unconventional superconductor Sr2RuO4, Phys. Rev. B 88, 094504 (2013)
M. Gradhand, K. I. Wysokinski, J. F. Annett, and B. L. Györffy
- The Berry curvature of the Bogoliubov quasiparticle Bloch states in the unconventional superconductor Sr2RuO4, J. Phys. - Cond. Matter, Vol 26 No 27, Published 17 June 2014
M. Gradhand, J. F. Annett
(See online at https://doi.org/10.1088/0953-8984/26/27/274205)
