A DFT + DMFT approach for nanosystems

We propose a combined density-functional-theory–dynamical-mean-field-theory (DFT + DMFT) approach for reliable inclusion of electron–electron correlation effects in nanosystems. Compared with the widely used DFT + U approach, this method has several advantages, the most important of which is that it takes into account dynamical correlation effects. The formalism is illustrated through different calculations of the magnetic properties of a set of small iron clusters (number of atoms 2 ≤ N ≤ 5). It is shown that the inclusion of dynamical effects leads to a reduction in the cluster magnetization (as compared to results from DFT + U) and that, even for such small clusters, the magnetization values agree well with experimental estimations. These results justify confidence in the ability of the method to accurately describe the magnetic properties of clusters of interest to nanoscience.

[1]  Jaejun Yu,et al.  Structure and magnetism of small Gd and Fe nanoclusters: LDA+U calculations , 2009 .

[2]  S. Florens.  Nanoscale dynamical mean-field theory for molecules and mesoscopic devices in the strong-correlation regime. , 2007, Physical review letters.

[3]  P. Entel,et al.  Electron correlation effects in the Fe dimer. , 2006, The journal of physical chemistry. A.

[4]  James Freericks,et al.  Transport in Multilayered Nanostructures: The Dynamical Mean-Field Theory Approach , 2006 .

[5]  R. Scalettar,et al.  Realistic investigations of correlated electron systems with LDA + DMFT , 2006 .

[6]  J. Freericks,et al.  Nonequilibrium dynamical mean-field theory. , 2006, Physical review letters.

[7]  P. Entel,et al.  Competing structural and magnetic effects in small iron clusters , 2006 .

[8]  C. Marianetti,et al.  Electronic structure calculations with dynamical mean-field theory , 2005, cond-mat/0511085.

[9]  J. A. Alonso.  Structure and Properties of Atomic Nanoclusters , 2005 .

[10]  I. Božović,et al.  Strongly correlated electron materials : physics and nanoengineering : 31 July-4 August, 2005, San Diego, California, USA , 2005 .

[11]  Ž. Šljivančanin,et al.  Supported fe nanoclusters: evolution of magnetic properties with cluster size. , 2003, Physical review letters.

[12]  W. Harrison.  Elementary Electronic Structure , 1999 .

[13]  Alfredo Pasquarello,et al.  Fully Unconstrained Approach to Noncollinear Magnetism: Application to Small Fe Clusters , 1998 .

[14]  M. Katsnelson,et al.  Ab initio calculations of quasiparticle band structure in correlated systems: LDA++ approach , 1997, cond-mat/9707127.

[15]  D. Salahub,et al.  Structure, bonding, and magnetism of small Fen, Con, and Nin clusters, n ≤ 5 , 1997 .

[16]  Piscataway,et al.  First-principles calculations of the electronic structure and spectra of strongly correlated systems: dynamical mean-field theory , 1997, cond-mat/9704231.

[17]  A. Lichtenstein,et al.  First-principles calculations of electronic structure and spectra of strongly correlated systems: the LDA+U method , 1997 .

[18]  W. Krauth,et al.  Dynamical mean-field theory of strongly correlated fermion systems and the limit of infinite dimensions , 1996 .

[19]  Jarrell,et al.  Holstein model in infinite dimensions. , 1993, Physical review. B, Condensed matter.

[20]  V. Anisimov,et al.  Band theory and Mott insulators: Hubbard U instead of Stoner I. , 1991, Physical review. B, Condensed matter.

[21]  D. Vollhardt,et al.  Correlated Lattice Fermions in High Dimensions , 1989 .

[22]  Fye,et al.  Monte Carlo method for magnetic impurities in metals. , 1986, Physical review letters.

[23]  Cox,et al.  Magnetic behavior of free-iron and iron oxide clusters. , 1985, Physical review. B, Condensed matter.

[24]  A. M. Tsvelick,et al.  Exact results in the theory of magnetic alloys , 1983 .

[25]  T. I. Morrison,et al.  Extended-x-ray-absorption-fine-structure study of small Fe molecules isolated in solid neon , 1982 .

[26]  G. Shenoy,et al.  EXAFS study of iron monomers and dimers isolated in solid argon , 1980 .

[27]  J. C. Slater,et al.  Simplified LCAO Method for the Periodic Potential Problem , 1954 .