Ferroelectricity in underdoped La-based cuprates.
Doping a "parent" antiferromagnetic Mott insulator in cuprates leads to short-range electronic correlations and eventually to high-Tc superconductivity. However, the nature of charge correlations in the lightly doped cuprates remains unclear. Understanding the intermediate electronic phase in the phase diagram (between the parent insulator and the high-Tc superconductor) is expected to elucidate the complexity both inside and outside the superconducting dome, and in particular in the underdoped region. One such phase is ferroelectricity whose origin and relation to the properties of high-Tc superconductors is subject of current research. Here we demonstrate that ferroelectricity and the associated magnetoelectric coupling are in fact common in La-214 cuprates namely, La2-xSrxCuO4, La2LixCu1-xO4 and La2CuO4+x. It is proposed that ferroelectricity may result from local CuO6 octahedral distortions, associated with the dopant atoms and clustering of the doped charge carriers, which break spatial inversion symmetry at the local scale whereas magnetoelectric coupling can be tuned through Dzyaloshinskii-Moriya interaction.
Crete Center for Quantum Complexity and Nanotechnology, University of Crete, Heraklion 71003, Greece.|IESL-FORTH, Vassilika Vouton, Heraklion 71110, Greece.
Z
Z
Viskadourakis
Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore.
S S
SS
Sunku
Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark.
S
S
Mukherjee
Niels Bohr Institute, University of Copenhagen, Copenhagen DK-2100, Denmark.
B M
BM
Andersen
National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki 305-8562, Japan.
T
T
Ito
Materials and Structures Laboratory, Tokyo Institute of Technology, Kanagawa 226-8503, Japan.
T
T
Sasagawa
Crete Center for Quantum Complexity and Nanotechnology, University of Crete, Heraklion 71003, Greece.|Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371 Singapore.|Department of Physics, University of Crete, Heraklion 71003, Greece.
C
C
Panagopoulos