Ultra‐Fast Control of Magnetic Relaxation in a Periodically Driven Hubbard Model |
| |
| Authors: | Juan Jose Mendoza‐Arenas Fernando Javier Gómez‐Ruiz Martin Eckstein Dieter Jaksch Stephen R Clark |
| |
| Institution: | 1. Departamento de Física, Universidad de los Andes, Bogotá D. C., Colombia;2. Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, United Kingdom;3. Max Planck Institute for the Structure and Dynamics of Matter, University of Hamburg CFEL, Hamburg, Germany;4. Department of Physics, University of Bath, Bath BA2 7AY, United Kingdom |
| |
| Abstract: | Motivated by cold atom and ultra‐fast pump‐probe experiments we study the melting of long‐range antiferromagnetic order of a perfect Néel state in a periodically driven repulsive Hubbard model. The dynamics is calculated for a Bethe lattice in infinite dimensions with non‐equilibrium dynamical mean‐field theory. In the absence of driving melting proceeds differently depending on the quench of the interactions to hopping ratio  from the atomic limit. For  decay occurs due to mobile charge‐excitations transferring energy to the spin sector, while for  it is governed by the dynamics of residual quasi‐particles. Here we explore the rich effects that strong periodic driving has on this relaxation process spanning three frequency ω regimes: (i) high‐frequency  , (ii) resonant  with integer l, and (iii) in‐gap  away from resonance. In case (i) we can quickly switch the decay from quasi‐particle to charge‐excitation mechanism through the suppression of ν0. For (ii) the interaction can be engineered, even allowing an effective  regime to be reached, giving the reverse switch from a charge‐excitation to quasi‐particle decay mechanism. For (iii) the exchange interaction can be controlled with little effect on the decay. By combining these regimes we show how periodic driving could be a potential pathway for controlling magnetism in antiferromagnetic materials. Finally, our numerical results demonstrate the accuracy and applicability of matrix product state techniques to the Hamiltonian DMFT impurity problem subjected to strong periodic driving. |
| |
| Keywords: | Ultrafast control antiferromagnetism Floquet theory non‐equilibrium dynamical mean‐field theory |
|
|
from the atomic limit. For 
decay occurs due to mobile charge‐excitations transferring energy to the spin sector, while for 
it is governed by the dynamics of residual quasi‐particles. Here we explore the rich effects that strong periodic driving has on this relaxation process spanning three frequency ω regimes: (i) high‐frequency 
, (ii) resonant 
with integer l, and (iii) in‐gap 
away from resonance. In case (i) we can quickly switch the decay from quasi‐particle to charge‐excitation mechanism through the suppression of ν0. For (ii) the interaction can be engineered, even allowing an effective 
regime to be reached, giving the reverse switch from a charge‐excitation to quasi‐particle decay mechanism. For (iii) the exchange interaction can be controlled with little effect on the decay. By combining these regimes we show how periodic driving could be a potential pathway for controlling magnetism in antiferromagnetic materials. Finally, our numerical results demonstrate the accuracy and applicability of matrix product state techniques to the Hamiltonian DMFT impurity problem subjected to strong periodic driving.