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Condensed Matter Physics Seminar - Stefano Bonetti

Science and Information Technology

This is part of a virtual seminar series in theoretical condensed matter and atomic physics, with the aim to connect researchers working at different Nordic universities. This seminar by Stefano Bonetti from Stockholm University is titled "Terahertz electric-field driven magnetism in SrTiO3".

Seminar
Date
8 Nov 2021
Time
16:15 - 17:15
Location
Digitally via Zoom

Stefano Bonetti: Terahertz electric-field driven magnetism in SrTiO3

Abstract

The emergence of collective order in matter is among the most fundamental and intriguing phenomena in physics. In recent years, the ultrafast dynamical control and creation of novel ordered states of matter not accessible in thermodynamic equilibrium is receiving much attention. Among those, the theoretical concept of dynamical multiferroicity has been introduced to describe the emergence of magnetization by means of a time-dependent electric polarization in non-ferromagnetic materials. In simple terms, a large amplitude coherent rotating motion of the ions in a crystal induces a magnetic moment along the axis of rotation. However, the experimental verification of this effect is still lacking. Here, we provide the first evidence of room temperature magnetization in the archetypal paraelectric perovskite SrTiO3 due to this mechanism. To achieve it, we resonantly drive the infrared-active soft phonon mode with intense circularly polarized terahertz electric field, and detect a large magneto-optical Kerr effect. A simple model, which includes two coupled nonlinear oscillators whose forces and couplings are derived with ab-initio calculations using self-consistent phonon theory at a finite temperature, reproduces our experimental observations on the temporal and frequency domains.

The seminar is held digitally via Zoom

Zoom-link: https://nordita.org/zoom/nvcms

Read more about the seminar series

Condensed Matter Physics Seminar