Abstract | Ferromagnets and ferroelectrics are “ferroic” materials that exhibit spontaneous order of magnetic and electric dipoles below a critical temperature, respectively. The elementary quasiparticle excitations of magnetic materials are known as spin waves or their quanta “magnons”, which have been extensively studied in the field of spintronics as the carriers of spin currents. However, it has been an entirely open question whether an analogous quasi-particle exists in ferroelectric materials - an important material class with many technological applications. In this talk, I positively answer this fundamental question by proposing a new class of quasi-particles “ferrons” in ferroelectrics that carry energy as well as an electric dipole [1,2] and address the associated electric polarization transport [3]. Based on the ferron spectrum, we predict temperature-dependent pyroelectric and electrocaloric properties, electric-field-tunable heat transport that has been confirmed by the experiment [4], ferron-photon hybridization, and non-local ferron drag thermoelectric effect in ferroelectric van der Waals heterostructure [5]. References [1]P. Tang et al., Phys. Rev. B 106, L081105 (2022). [2]P. Tang et al., Phys. Rev. B109, L060301 (2024). [3]P. Tang et al., Phys. Rev. Lett. 128, 047601(2022). [4]B. L Wooten et al., Science Advance 9 eadd7194 (2023). [5]P. Tang et al. Phys. Rev. B 107, L121406 (2023).
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