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Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
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Ferroelectricity by Bose-Einstein condensation in a quantum magnet.
S Kimura1, K Kakihata1, Y Sawada1
1Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan.
Nature Communications
|September 27, 2016
Summary
Bose-Einstein condensation in magnons induces electric polarization in quantum magnets, revealing a novel magnetoelectric effect. This finding introduces soft ferroelectricity and expands the multifunctionality of quantum magnetic materials.
Area of Science:
- Condensed Matter Physics
- Quantum Magnetism
- Materials Science
Background:
- Bose-Einstein condensation (BEC) is a quantum phenomenon arising from statistical properties of identical integer-spin particles.
- BEC leads to macroscopic quantum coherence, manifesting in properties like superfluidity and the Josephson effect.
- BEC is observed in systems beyond superfluids and superconductors, including quasi-particles like magnons in solids.
Purpose of the Study:
- To investigate the emergence of electric polarization in quantum magnets due to Bose-Einstein condensation of magnons.
- To explore the resulting magnetoelectric effect and ferroelectricity in TlCuCl3.
Main Methods:
- Studying the quantum coherence of magnon quasi-particles.
- Observing spontaneous electric polarization in the quantum magnet TlCuCl3.
- Analyzing the symmetry breaking associated with magnon Bose-Einstein condensation.
Main Results:
- Quantum coherence in the magnon Bose-Einstein condensate of TlCuCl3 leads to spontaneous electric polarization.
- A significant magnetoelectric effect is observed.
- Soft ferroelectricity is realized due to O(2) symmetry breaking by the magnon BEC.
Conclusions:
- Magnon Bose-Einstein condensation can induce ferroelectricity and magnetoelectric effects in quantum magnets.
- This discovery opens new avenues for exploring the multifunctional properties of quantum magnetic materials.
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