Hybrid improper Ferroelectricity

Hybrid Improper Ferroelectricity in a Multiferroic and Magnetoelectric Metal-Organic Framework A. Stroppa, P. Barone, P. Jain, J. M. Perez-Mato, and S. Picozzi

Adv. Mater. 2013

On the basis of first-principles calculations, we design a novel Cr-based metal-organic framework to be both multiferroic and magnetoelectric. The compound shows a “double-hybrid” nature: it is a hybrid organic-inorganic compound and it shows hybrid improper ferroelectricity. Here, the coupling of non-polar distortions, such as Jahn-Teller pseudo-rotations and tilting, pave the way to a polar behavior, with the coupling being realized through hydrogen bonds.

NEW RELEASE: VASP.5.3.3

A new release of VASP, version 5.3.3.18Dec2012, is available for download now (for all holders of a valid “VASP.5.2” license)!

P.S.: Some users have experienced download problems with the Internet Explorer (specifically with the japanese version of IE8). If you run into this problem please try another browser (firefox 3.0, Chrome, etc etc).

NEW RELEASE: P4VASP 0.3.23

It has been quite some time since the last release, but now finally a new version of p4vasp is released!

P4vasp 0.3.23 contains several improvements and bug fixes:

  • Inverse Participation Ratio available in electronic applet.
  • Speed of MD can be set in Structure viewer/Control.
  • Numeric/Numarray support has been replaced by the NumPy support (including in the velocity autocorelation applet).
  • Bug in the Dielectric function has been fixed.

Bugfix: VASP.5.2.11 on IBM

Compiling with the xlf compiler (version 12.1.0.9) and running on an IBM SP6 revealed several bugs (unbelievable what the ifort compiler is able to swallow and still produce running code).

N.B.: We recommend this update to all users, not only those using the xlf compiler.

Bugfix: in vdwforcefield.F

Bugfix to vdwforcefield.F: ) C6 and R0 parameters can be defined per type of atoms in the POSCAR file. Previously they could be defined only per element.

Bugfix: in VASP.5.2.11

Bugfix to vdwforcefield.F: ) A workaround so that Grimme’s method works for Xe POTCAR files wrongly labelled “X”.

Corrected mistakes in makefile.ibm_hlrn and makefile.ibm_hlrn-serial

Bugfix: in VASP.5.2.11

Bugfix to mlwf.F: ) Projections were calculated incorrectly in the noncollinear case.

Corrected mistakes in makefile.ibm_hlrn and makefile.ibm_hlrn-serial

Bugfix: in VASP.5.2.11

Unfortunately every new release immediately triggers a few bugfixes:

Bugfix to nmr.F: ) One call to SETDIJAVEC should have been to SETDIJ_AVEC_ONE_CENTER

Bugfix to us.F: ) An END SUBROUTINE SETDIJAVEC should have been END SUBROUTINE SETDIJ_AVEC_ONE_CENTER

Bugfix to david_inner.F: ) Could not be compiled without scaLAPACK. Can be now, but will not work correctly [still heavily under development anyway].

We are very sorry for the inconvience.

A multiferroic material to search for the permanent electric dipole moment of the electron

K. Z. Rushchanskii, S. Kamba, V. Goian, P. Vaněk, M. Savinov, J. Prokleška, D. Nuzhnyy, K. Knížek, F. Laufek, S. Eckel, S. K. Lamoreaux, A. O. Sushkov, M. Ležaić, and N. A. Spaldin

Nature Materials 9, 649 (2010).

We describe the first-principles design and subsequent synthesis of a new material with the specific functionalities required for a solid-state-based search for the permanent electric dipole moment of the electron. We show computationally that perovskite-structure europium barium titanate should exhibit the required large and pressure-dependent ferroelectric polarization, local magnetic moments and absence of magnetic ordering at liquid-helium temperature. Subsequent synthesis and characterization of Eu0.5Ba0.5TiO3 ceramics confirm the predicted desirable properties.