Fig. 4 showsthecalculatedresultsofthetotalandpartial
density ofstates(DOS)ofBa2CeCoO6. Itisclearthatthereisan
energy gapattheFermilevelinthespin-upstates,whilethespin-
downstatesaremetallic.Theenergygapinthespin-upbandand
metallicity inthespin-downbandcause100%spinpolarizationat
the Fermilevel.Non-zerospin flip gapprovesthatthiscompound
is atruehalf-metallicferromagnet.Itcanbeseenthatthetotal
DOS aremainlycontributedbyCo-3d and O-2p electrons inthe
energy rangeof 3.0 eVtoFermilevel.AbovetheFermilevel,the
Ba-5d states makeamaincontributiontothetotalDOS.Con-
sidering thepeaksneartheFermilevel,we find thatthepresence
of anoctahedralcrystal field ofthesixoxygenatomsaroundthe
Co siteresultsinasplittingofthe five-fold degenerateCo-3dstates
into doublydegenerateeg (dz2 and dx2 y2 ) stateswithhigher
energy andtriplydegeneratet2g (dxy, dyz and dzx ) stateswith
lowerenergyforbothspin-upandspin-downchannels.Thespin-
splitting ofabout0.63eVmakesthespin-downstatesofthetriply
degeneratet2g crosstheFermilevel,resultinginthepartial
occupation, andspin-upt2g states areoccupiedandlieatabout
0.49eVundertheFermilevel.Boththeeg states ofspin-down
and spin-uplyingrespectivelyatabout2.0and2.1eVarenot
occupied.
The calculatedvaluesofthetotalandpartialmagneticmoment
of thiscompoundarelistedin Table2. Thevalueofthetotal
magnetic momentsispredictedtobe1.0 μB . Forthiscompound,
the maincontributiontothetotalmagneticmomentcomesfrom
the CoandOatoms,whilethecontributionsofBaandCeatoms
areverysmall.
Fig. 4 showsthecalculatedresultsofthetotalandpartialdensity ofstates(DOS)ofBa2CeCoO6. Itisclearthatthereisanenergy gapattheFermilevelinthespin-upstates,whilethespin-downstatesaremetallic.Theenergygapinthespin-upbandandmetallicity inthespin-downbandcause100%spinpolarizationatthe Fermilevel.Non-zerospin flip gapprovesthatthiscompoundis atruehalf-metallicferromagnet.ItcanbeseenthatthetotalDOS aremainlycontributedbyCo-3d and O-2p electrons intheenergy rangeof 3.0 eVtoFermilevel.AbovetheFermilevel,theBa-5d states makeamaincontributiontothetotalDOS.Con-sidering thepeaksneartheFermilevel,we find thatthepresenceof anoctahedralcrystal field ofthesixoxygenatomsaroundtheCo siteresultsinasplittingofthe five-fold degenerateCo-3dstatesinto doublydegenerateeg (dz2 and dx2 y2 ) stateswithhigherenergy andtriplydegeneratet2g (dxy, dyz and dzx ) stateswithlowerenergyforbothspin-upandspin-downchannels.Thespin-splitting ofabout0.63eVmakesthespin-downstatesofthetriplydegeneratet2g crosstheFermilevel,resultinginthepartialoccupation, andspin-upt2g states areoccupiedandlieatabout0.49eVundertheFermilevel.Boththeeg states ofspin-downand spin-uplyingrespectivelyatabout2.0and2.1eVarenotoccupied.The calculatedvaluesofthetotalandpartialmagneticmomentof thiscompoundarelistedin Table2. Thevalueofthetotalmagnetic momentsispredictedtobe1.0 μB . Forthiscompound,the maincontributiontothetotalmagneticmomentcomesfromthe CoandOatoms,whilethecontributionsofBaandCeatoms
areverysmall.
การแปล กรุณารอสักครู่..