Spin-Dipole Coupling as Information Storage and Processing in Multiferroics

演讲人: Prof. Jun Hee Lee School of Energy, Ulsan National Institute of Science & Technology (UNIST)
时间: 2016-11-18 16:00-2016-11-18 18:00

Multiferroics, where permanent electric dipoles strongly couple to magnetic spins [1-3], are emerging as a novel tool for information technology. While conventional memory materials employ either magnetic (MRAM) or electric (FeRAM) dipole moment as one bit information storage (0 or 1), the strong coupling between them can be used for realizing two-bits memory devices where four stable states, that both magnetic and electric dipole make, can be allotted as (00), (01), (10), and (11). I will show how to induce the strong spin-electric dipole coupling in multiferroic compounds for the multiple information storage. Second, magnon, which is a quasi-particle from spin-wave excitations [4], exhibits exotic properties such as Bose-Einstein condensations and supercurrent which can be used for information generation and delivery in logic-gates. In particular, I will talk about electromagnon whose spin excitations are controllable by electric field [5], and its coupling with THz light to design optical diode with one way transparency in the spin-wave excitations [6].

[1] J. H. Lee* & K. Rabe, Physical Review Letters 104, 207204 (2010). 
[2] J. H. Lee* & K. Rabe, Physical Review Letters 107, 067601 (2011).
[3] S. Calder, J. H. Lee* et al., Nature Communications 6, 8916 (2015).
[4] J. H. Lee* et al., New Journal of Physics 18, 043025 (2016).
[5] J. H. Lee* and R. Fishman, Physical Review Letters 115, 207203 (2015).
[6] I. Kezsmarki, U. Nagel, S. Bordacs, R. Fishman, J. H. Lee et al., Physical Review Letters 115, 127203 (2015).


Jun Hee Lee is assistant professor at Ulsan National Institute of Science & Technology (UNIST) in South Korea. He received his PhD in 2008 from Seoul National University in Korea. He undertook three postdoc research fellowships at Rutgers University (Physics, 2008~2011), Princeton University (Chemistry, 2011~2013), and at Oak Ridge National Laboratory (Materials, 2013~2015). In 2015, he joined UNIST as an assistant professor in School of Energy. His research covers a broad range of topics including multiferroicity, geometric frustration, quantum-phase transitions, magnon dynamics, photocatalysts, and light-matter interactions in complex oxides.