Thermal Magnetic Fluctuations of a Ferroelectric Quantum Critical Point

TL;DR

This paper explores how electric dipole fluctuations near a ferroelectric quantum critical point can induce measurable magnetic responses, highlighting potential for experimental detection in materials like strontium titanate.

Contribution

It demonstrates the finite-temperature magnetic susceptibility enhancement near a ferroelectric quantum critical point and proposes strontium titanate as a candidate for observing dynamic multiferroicity.

Findings

Magnetic susceptibility is enhanced near the FE QCP.

Strontium titanate shows detectable magnetic response.

Finite temperature effects increase magnetic fluctuations.

Abstract

Entanglement of two different quantum orders is of an interest of the modern condensed matter physics. One of the examples is the dynamical multiferroicity, where fluctuations of electric dipoles lead to magnetization. We investigate this effect at finite temperature and demonstrate an elevated magnetic response of a ferroelectric near the ferroelectric quantum critical point (FE QCP). We calculate the magnetic susceptibility of a bulk sample on the paraelectric side of the FE QCP at finite temperature and find enhanced magnetic susceptibility near the FE QCP. We propose quantum paraelectric strontium titanate (STO) as a candidate material to search for dynamic multiferroicity. We estimate the magnitude of the magnetic susceptibility for this material and find that it is detectable experimentally.