Berlin 2012 – scientific programme

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O: Fachverband Oberflächenphysik

O 2: Focussed session: Frontiers of electronic structure theory: Strong correlations from first principles I (jointly with TT)

O 2.3: Talk

Monday, March 26, 2012, 11:15–11:30, HE 101

Hubbard U and Hund's J from the constrained Random Phase Approximation within a full-potential linearized augmented plane wave approach: trends for 3d and 4d transition metal perovskites — •Loig Vaugier¹, Hong Jiang², and Silke Biermann¹ — ¹CPHT, Ecole Polytechnique, Palaiseau, France — ²College of Chemistry, Peking University, Beijing 100871, China

Determining the Coulomb interactions in real materials presents a serious challenge for first principles approaches. In 2004, a systematic way - called constrained-RPA (cRPA) - of calculating the Hubbard U and Hund's rule J parameters from first-principles has been proposed by Aryasetiawan and coworkers [1]. We have implemented the cRPA method in the framework of the Full Potential Linear Augmented Plane Waves method as implemented in the Wien2k code [2]. Our scheme permits us to calculate the Hubbard interactions in the same basis in which combined LDA+DMFT calculations are performed within the implementation of [3], yielding a fully consistent first-principles scheme. As an application of cRPA, we have calculated Hubbard U's and Hund J's for cubic 3d and 4d transition metal perovskites [4]. In contrast to what is usually assumed, the trend is not necessarily monotonic. Our work emphasizes the dependence of U and J on the choice of the one-electron part of the Hamiltonian.

[1] Aryasetiawan et al. PRB 70, 195104 (2004)

[2] Blaha et al., Wien2k, (2001)

[3] Aichhorn et al., PRB 80, 085101 (2009)

[4] Vaugier, Jiang and Biermann, in preparation