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Seminarium om kondenserade materiens fysik - Stefano Bonetti

Naturvetenskap & IT

Detta är en del av en digital seminarieserie i kondenserade materiens fysik och atomfysik, med syfte att koppla samman forskare från olika nordiska universitet. Stefano Bonetti från Stockholms universitet håller ett seminarium med titeln "Terahertz electric-field driven magnetism in SrTiO3".

Seminarium
Datum
8 nov 2021
Tid
16:15 - 17:15
Plats
Digitalt via Zoom
Ytterligare information
Zoom-länk till seminariet

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.

Seminariet hålls digitalt via Zoom

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

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Seminarium om kondenserade materiens fysik