3,065 research outputs found
Spectral density and metal-insulator phase transition in Mott insulators within RDMFT
We present a method for calculating the spectrum of periodic solids within
reduced density matrix functional theory. This method is validated by a
detailed comparison of the angular momentum projected spectral density with
that of well established many-body techniques, in all cases finding an
excellent agreement. The physics behind the pressure induced insulator-metal
phase transition in MnO is investigated. The driving mechanism of this
transition is identified as increased crystal field splitting with pressure,
resulting in a charge redistribution between the Mn and symmetry
projected states.Comment: arXiv admin note: text overlap with arXiv:0912.111
Reduced Density Matrix Functional for Many-Electron Systems
Reduced density matrix functional theory for the case of solids is presented
and a new exchange correlation functional based on a fractional power of the
density matrix is introduced. We show that compared to other functionals, this
produces more accurate results for both finite systems. Moreover, it captures
the correct band gap behavior for conventional semiconductors as well as
strongly correlated Mott insulators, where a gap is obtained in absence of any
magnetic ordering.Comment: 4 figs and 1 tabl
Enhanced excitonic effects in the energy loss spectra of LiF and Ar at large momentum transfer
It is demonstrated that the bootstrap kernel [\onlinecite{sharma11}] for
finite values of crucially depends upon the matrix character of the
kernel and gives results of the same good quality as in the limit. The bootstrap kernel is further used to study the
electron loss as well as absorption spectra for Si, LiF and Ar for various
values of . The results show that the excitonic effects in LiF and Ar
are enhanced for values of away from the -point. The reason
for this enhancement is the interaction between the exciton and high energy
inter-band electron-hole transitions. This fact is validated by calculating the
absorption spectra under the influence of an external electric field. The
electron energy loss spectra is shown to change dramatically as a function of
Engaging Students Engaging Industry Engaging Enterprise
A reflective piece on how a small team of students and academics gained more awareness of their own sense of enterprise and creativity. The case study examines the phases and crisis points of the whole event process and identifies some of the key learning outcomes for all involved
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