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Chemical bond and electronic structure in \123 and 124 superconductors
Physica C 185- 189 (1991) 859-860 North-Holland
Chemical Bond and E l e c t r o n i c Struoture i n ~ t22 and 124 S u p e r c o n d u c t o r s
U-Hyon Paek, Man Shick Son and gee Hag Lee* Department. o f Chemist.vy, (iyeongsang N a t i o n a l U n i v e r s i t y , J i n ~ u , 660-701, Korea *Department o f C h e m i s t r y , Wongwang U n i v e r s i t y , I r l , 570-749, Korea
In o r d e r t o com~elat.e t h e s t r u c t u r a l u n i t s and u n i t ( : e l l s in t h e Y123 and Y124 systems, ~e have c a r r i e d o u t ASED-MO c a l c u l a t i o n u i t h charged model c l u s L e r s Mgh and w i t h o u t p o i n t charges. The chargeO model c l u s t e r s f o r t h e Y122 system were, Cu04 -0, Cu{ls - 8 , Cu04 -~ and Cu3[112- I 8 w i t h o u t p o i n t c h a r g e s and CuO4H4- a , CuOsH4-4, CuO4H2-4 and CuaOlzHIo -u w i t h p o i n t c h a r g e s . 1'he charged model c l u s t e r s f o r t h e YI24 system were. CU[)4-6. CuOs-8, CuaI.]6-8 and CU4014-20 w i t h o u t p o i n t charges and CuO~H4- z , CuOsH4-~, CI1206H4-4 and CU4I]I4H/2 -8 w i t h point, c h a r g e s . We found t h a t t h e charged model c l u s t e r s r e l a t i n g t o t h e s t r u c t u r a l u n i t s (;an nor d e ~ c r i b e t h e re.al pr()pe)'l.i~s o f t h e Y122 and t.h~ Y124 super(endue:Cars, so re,, n(+ed t~, use the c h a r g e d model c l u s t e r ~ r e l a t i n g t(.) t h e e n t i r e u n i t c e l l . The o x i d a t i o n s t a t e o f Cu in t h e l a y e r o f Y123 system i s h i g h e r t h a n t h e o x i d a t i o n s t a t e o f Cu in t h e l a y e r o f Y124 system.
[ d i s p l a c e d by b/2 alnng t h e b direx:tion]
I. INTRODUCTION
-O-Cu(I)-O(4)-Cu(2) s t r u c t u r a l
1"he high-To super(~Jnduetor YBazCu3Ov-~ (cal led Y123 system)
is
~ : - d i r e c t i n n was a l s o c a l l e d t h e s t u b .
a cx~)rdination comv)und foretold
In order t.<) gain a better understanding of the
by t h e linkage o f Cu-O p l a n e s and t.etPagonal and pyPamida[ unit, w i t h Y and Ba embedded. al.~
unit. along (.he
high-T( YI23 and Y124 supe~::onduc,tor~, it is
Beno e t
import.anl., t o
ident, i f i e d cr%,st,M st,Puature o f t h e Y123
c:c)rr'e
Ia t e t.ho st.r!lG{.ilFa ] u n i t s ~'*ld
system u s i n g h i g h - r ~ s o l u t , ion neut.ron powder
t.h,~ unit. ,;ell wit.h s e m i - e m p i r i c a l MO ( : a l t u l a t i o n ,
d i ffraci.ion.
atom s u p ~ r p o s i t i o n and e!o(::tr~m d(q(~;alizal.ion l)rd~,:ulm
h,:x:;ording to Mar:~h et. a l .z wh- identified t,he
,,~ i,;~,~i (A~;ED-MI)) ~ :~I" th," YI?/~ and the
Y] 24 crs, sta.1 stmK;tuPe usi ng X-ray d i f f r a c t i o n ,
YI24 s u p e r c o n d u c t o r s .
t h e h igh-T¢ s u p e r c o n d u c t o r gBaaCu40a ( c a l l e d Y124
was t o o b b a i n the o x i d a t i o n s t a t e 4 and the hole o f
system) caa be c o n s i d e r e d as t.wo YBa2Cu307-~. (;el l s
Cu(I) and Cut2) and {:he envirxmmental e f f e c t s i n
joined chain-to-chain with t.he second (,ell
t h e c h a r g e d model c l u s t e r s w i t h l a y e r , chain and
displaced b/2 along b-direction.
s t u b w i t h o r without p o i n t c h a r g e s .
The st,ruc, t.ural unit, in the v19~ system (x)n~ains
The pur~vse o f t h i s work
In t h i s paper,
the hole o f Cu atom [s taken i n t o account: Hole=lO- EQ
2 c o p p e r atoms ( c a l l e d Cut2)) with a squar~ plan, °,` o r a square pyramidal c o o r d i n a t i ( ) n by 4 o r 5
~h~r'~ Q i~; f,he t o t a l popular.ion c)f oc,:(:upied Cu
oxygen atoms and i (;upper atom O;a! led Cut1) ) m t . h
atomic: o r b i t a l .
a aquar-e p l a n a r ..... -"~:~','-;-'~ by "~ . . . . . . . . . .
+ .....
?.. EI.ECTRIINIC STR[ICTIKFN ANI) PI~)PERTIFS
The' YI24 system c.ontaln.'~ 2 (x)pp~r aLnms ((~al led
Fc)r" the Y[23 and t.he Y124 sy~;t.ems, ~,~ used Ibe
Cut2)) wii.h a s q u a r e p l a n a r o r a square pyramidal c;oordlnatic)n by 4 o r 5 oxygen atoms and 2 c:opper
fractional
atoms ( c a l l e d C u ( t ) ) ~ i t h a squa,'~ planar"
a l . 1 and Marsh e t a l . z.
c o o r d i n a t i o n by 4 oxygen at.ore.% In the Y123
(:lust.ers a r e as follows: (a) f o r t h e (:harged mc:del
system, t h e Cu(2) - 0 ( 4 ) -Cu( t ) - 0 ( 4 ) -Cu (7.) stru(;t.ura 1
clusters
unit. a l o n g the c - d i ) ~ ( : t i o n was (.a~led the s t u b .
YTda2Cu3{lT-×: Cu04 -b, l_a; Cu()5-8, ~At; Cu04- ° , .'~;
In
the YI24 system, t h e C u ( 2 ) - O ( 4 ) - C u ( l ) -
0921-4534/91/$03.50 © 1991 - Elsevier Science Publishers B.V.
atomic: (:(~)rdinates o b t a i n e d by Beno et.
The charged m,)del
r e p r e s e n t i n g the suw-~;onduMs~r
Cu~Otz-ta, .4a; CuOail4" z , _Sa; CuOsH4-4. ~ ;
All fights reserved.
860
U-H. Paek et aL / 1"123and 124 superconductors
CuO41la-4, 7_a; and CuaOlaHlo -a, ._I~t. (b) for the
Orbital)
charged model c l u s t e r s r~pr'e.senting VBazCu4IJa:
{.o fol low di f f e r ' e n t pat, t,er-ns.
in t h e YI23 and the v124 systems iu .~een
Cu04"% _l_b; CuOs-a, _2b; Cuztl8 -a, 3_b; cu4rl,4 - z ° , _4b; CuO4H4-a, ~.~; CuOsH4 "~, 6._bb;CuzO6H4 -4, ?.bb; and Oul4Ol4Hla -8, 8._bb. In the ASDE-MO c a l c u l a t i o n s ,
E(eV)
8
ot
---
k
m
ohms'e, t,he nominal oharges c,F eac.h ion aa follows: +2 f o r Cu ions; -2 f o r 0 ions; and +! for tt ions. Table I sho~es the o x i d a t i o n s t a t e and the hole of Cu atoms in the YIPZt and t h e Y124 sysCems.
-5
5
The
t.~) Cu04"6 charged mod~l clust.ers in Ylg3 are the
HEOL
oharged model cluster of Cu(2) in the layer" and
-10
" [
-
1
I
- -
--
~
.
.
.
.
~I!_=
I I
--
I~
.
HEOL
10
.~,ii-=II
Cu(1) in the Ghain. It. is clear from the oxidation states that. the Cu atoms in a single c:hain of the -1/,
Y123 system act as electron donors Lo the Cu
illiIiIII
la 2 a ~ 6 a T a ~
,, w -
I-'',, I
-qg IbZb3b4bSb6bTbBb
at, om.~ in layers, l~e Cu at.(,m.~ in a double chain o f the Y124 system plays Ylg3 system
t h e same r n l e as in I:he
git,azawa s has d e f i n i t e l y shown t h a t
the o r i t lea l temI~,rature t,f s u p e m o n d u c l ~ s inorvases as the hole conceni:ratirm increases.
In
Fig. 1. Molee,u l a r o r b i t a l level diagrams f o r the oharged model c l u s t e r s l a .--~_ as tier.ermined by ASE[I-MO (; 1usteP ca l c u l a t i o n s .
Fig. 2. Molecular o r b i t a l level diagrams for t h e charged model c l u s t e r s !b--g.b as detern~ined by ASEI)-MO c l u s t e r ca I cu I at. tons.
the s t u b u i t h o u t point cha~ges, [.hehole of the Cu atom in the layer, and the c h a i n o f the YI?21 sysLem REFFPJSNCFN
is h i g h e r than iL is in the YI24 system. 'Fable I. The ( x i d a t i o n b t a t e and the Hole of Cu(1) and Cu(2) o f the YI23 and the Yl24 systems
I. M. A. Beno, t.. ~,derholm, D. W. Cat,me, l I , D. G. Hink~, J. D, dorgensen, J. l), Grace, and Ivan g. ~k:huller, C. /I. ~gr~. and K. Zhang, Appl. Phys. [ ~ t t . , 5I (1987) 57
~barged Model V N - - ] - h } i - d - a Y [ ; ; n - H;;]-o-- ] lUSl.er [ At.(Im | SlaLe " / YiZcVI c_'RGZ -6 . . . . l-e~C'_21I--!2_fi~o . . . . 0-,9~- l l- Cu0£ ~ - - T e - f f f f f J T - - 17Z_W!. . . . . . 6 . ~ . ~ d
2. P. Marsh, R. M. Fleming, M. L. Mandi(:h, A. }4. [~,.san(,olo, J. K~,, M. tfong and L. J. Mar%inez-Miranda, Nature, :.15.{4 (I988) I4I
['-CLiO.~_ . . . . . | - e U I C I 3 ] ~ - 71~6 ~6- . . . . . . .
0.-9"I-~--
-I
3. A. B. Anderson, J. Chem. Phys., 6g (1975) I187
g-¢i~oa_gga-rl c u ( D L L
L g~.1.~. . . .
.W~O_--1
/ Cu(2)]-- I,219 .......... ()~I87-_ ]
I cu_0i~E - - - T _ g ¢ l i 2 ? l 2-~ -foe . . . . .
0It0 I a Z ~
I Cu40i 4 - a - - ]-]~-u_-27!J~]-2{~O8---- LZ-gO_~1 _ _ [ -~ u_-(2~ -~.Ls_--g~ 70_7_b-gO7-]
I
.
ICu_OsH4- - ~ - - - f , O ~
_ _ _J . . . . . . . . . .
_~ c u _ . ~ ) . !
.
.
....
.
.
o ~i-~--1
Lal~__--L-_ Z.: L~_~I-I
Figm-e i and figure 2 shows the high-energy c~x;upied levet(HEOI,) in the oharged model c l u s t e r dashed-lines. gap between
4. X. H. Gao, Z. L. gin, H. gan,and X. I.. Wu, 5 ) l i d S t a t e Comm(micaLions, 76 (1990) 133
In figure. 1 and figus~. 2, the energy HOMO(Highest [kac;upied Molecular
O r b i t a l ) and I.[M}(t~c~e.st Un~×*~upied Molecular
5. Koichi l{itazawa, fIN J. RES. DEVEI,~)P., 33 (1988) 20i 6. Z. Zhi and Z. Ring-qi, S~,]id S t a t e Commun[cati,ms, 65 (I988) 5~9
Chemical Bond and E l e c t r o n i c Struoture i n ~ t22 and 124 S u p e r c o n d u c t o r s
U-Hyon Paek, Man Shick Son and gee Hag Lee* Department. o f Chemist.vy, (iyeongsang N a t i o n a l U n i v e r s i t y , J i n ~ u , 660-701, Korea *Department o f C h e m i s t r y , Wongwang U n i v e r s i t y , I r l , 570-749, Korea
In o r d e r t o com~elat.e t h e s t r u c t u r a l u n i t s and u n i t ( : e l l s in t h e Y123 and Y124 systems, ~e have c a r r i e d o u t ASED-MO c a l c u l a t i o n u i t h charged model c l u s L e r s Mgh and w i t h o u t p o i n t charges. The chargeO model c l u s t e r s f o r t h e Y122 system were, Cu04 -0, Cu{ls - 8 , Cu04 -~ and Cu3[112- I 8 w i t h o u t p o i n t c h a r g e s and CuO4H4- a , CuOsH4-4, CuO4H2-4 and CuaOlzHIo -u w i t h p o i n t c h a r g e s . 1'he charged model c l u s t e r s f o r t h e YI24 system were. CU[)4-6. CuOs-8, CuaI.]6-8 and CU4014-20 w i t h o u t p o i n t charges and CuO~H4- z , CuOsH4-~, CI1206H4-4 and CU4I]I4H/2 -8 w i t h point, c h a r g e s . We found t h a t t h e charged model c l u s t e r s r e l a t i n g t o t h e s t r u c t u r a l u n i t s (;an nor d e ~ c r i b e t h e re.al pr()pe)'l.i~s o f t h e Y122 and t.h~ Y124 super(endue:Cars, so re,, n(+ed t~, use the c h a r g e d model c l u s t e r ~ r e l a t i n g t(.) t h e e n t i r e u n i t c e l l . The o x i d a t i o n s t a t e o f Cu in t h e l a y e r o f Y123 system i s h i g h e r t h a n t h e o x i d a t i o n s t a t e o f Cu in t h e l a y e r o f Y124 system.
[ d i s p l a c e d by b/2 alnng t h e b direx:tion]
I. INTRODUCTION
-O-Cu(I)-O(4)-Cu(2) s t r u c t u r a l
1"he high-To super(~Jnduetor YBazCu3Ov-~ (cal led Y123 system)
is
~ : - d i r e c t i n n was a l s o c a l l e d t h e s t u b .
a cx~)rdination comv)und foretold
In order t.<) gain a better understanding of the
by t h e linkage o f Cu-O p l a n e s and t.etPagonal and pyPamida[ unit, w i t h Y and Ba embedded. al.~
unit. along (.he
high-T( YI23 and Y124 supe~::onduc,tor~, it is
Beno e t
import.anl., t o
ident, i f i e d cr%,st,M st,Puature o f t h e Y123
c:c)rr'e
Ia t e t.ho st.r!lG{.ilFa ] u n i t s ~'*ld
system u s i n g h i g h - r ~ s o l u t , ion neut.ron powder
t.h,~ unit. ,;ell wit.h s e m i - e m p i r i c a l MO ( : a l t u l a t i o n ,
d i ffraci.ion.
atom s u p ~ r p o s i t i o n and e!o(::tr~m d(q(~;alizal.ion l)rd~,:ulm
h,:x:;ording to Mar:~h et. a l .z wh- identified t,he
,,~ i,;~,~i (A~;ED-MI)) ~ :~I" th," YI?/~ and the
Y] 24 crs, sta.1 stmK;tuPe usi ng X-ray d i f f r a c t i o n ,
YI24 s u p e r c o n d u c t o r s .
t h e h igh-T¢ s u p e r c o n d u c t o r gBaaCu40a ( c a l l e d Y124
was t o o b b a i n the o x i d a t i o n s t a t e 4 and the hole o f
system) caa be c o n s i d e r e d as t.wo YBa2Cu307-~. (;el l s
Cu(I) and Cut2) and {:he envirxmmental e f f e c t s i n
joined chain-to-chain with t.he second (,ell
t h e c h a r g e d model c l u s t e r s w i t h l a y e r , chain and
displaced b/2 along b-direction.
s t u b w i t h o r without p o i n t c h a r g e s .
The st,ruc, t.ural unit, in the v19~ system (x)n~ains
The pur~vse o f t h i s work
In t h i s paper,
the hole o f Cu atom [s taken i n t o account: Hole=lO- EQ
2 c o p p e r atoms ( c a l l e d Cut2)) with a squar~ plan, °,` o r a square pyramidal c o o r d i n a t i ( ) n by 4 o r 5
~h~r'~ Q i~; f,he t o t a l popular.ion c)f oc,:(:upied Cu
oxygen atoms and i (;upper atom O;a! led Cut1) ) m t . h
atomic: o r b i t a l .
a aquar-e p l a n a r ..... -"~:~','-;-'~ by "~ . . . . . . . . . .
+ .....
?.. EI.ECTRIINIC STR[ICTIKFN ANI) PI~)PERTIFS
The' YI24 system c.ontaln.'~ 2 (x)pp~r aLnms ((~al led
Fc)r" the Y[23 and t.he Y124 sy~;t.ems, ~,~ used Ibe
Cut2)) wii.h a s q u a r e p l a n a r o r a square pyramidal c;oordlnatic)n by 4 o r 5 oxygen atoms and 2 c:opper
fractional
atoms ( c a l l e d C u ( t ) ) ~ i t h a squa,'~ planar"
a l . 1 and Marsh e t a l . z.
c o o r d i n a t i o n by 4 oxygen at.ore.% In the Y123
(:lust.ers a r e as follows: (a) f o r t h e (:harged mc:del
system, t h e Cu(2) - 0 ( 4 ) -Cu( t ) - 0 ( 4 ) -Cu (7.) stru(;t.ura 1
clusters
unit. a l o n g the c - d i ) ~ ( : t i o n was (.a~led the s t u b .
YTda2Cu3{lT-×: Cu04 -b, l_a; Cu()5-8, ~At; Cu04- ° , .'~;
In
the YI24 system, t h e C u ( 2 ) - O ( 4 ) - C u ( l ) -
0921-4534/91/$03.50 © 1991 - Elsevier Science Publishers B.V.
atomic: (:(~)rdinates o b t a i n e d by Beno et.
The charged m,)del
r e p r e s e n t i n g the suw-~;onduMs~r
Cu~Otz-ta, .4a; CuOail4" z , _Sa; CuOsH4-4. ~ ;
All fights reserved.
860
U-H. Paek et aL / 1"123and 124 superconductors
CuO41la-4, 7_a; and CuaOlaHlo -a, ._I~t. (b) for the
Orbital)
charged model c l u s t e r s r~pr'e.senting VBazCu4IJa:
{.o fol low di f f e r ' e n t pat, t,er-ns.
in t h e YI23 and the v124 systems iu .~een
Cu04"% _l_b; CuOs-a, _2b; Cuztl8 -a, 3_b; cu4rl,4 - z ° , _4b; CuO4H4-a, ~.~; CuOsH4 "~, 6._bb;CuzO6H4 -4, ?.bb; and Oul4Ol4Hla -8, 8._bb. In the ASDE-MO c a l c u l a t i o n s ,
E(eV)
8
ot
---
k
m
ohms'e, t,he nominal oharges c,F eac.h ion aa follows: +2 f o r Cu ions; -2 f o r 0 ions; and +! for tt ions. Table I sho~es the o x i d a t i o n s t a t e and the hole of Cu atoms in the YIPZt and t h e Y124 sysCems.
-5
5
The
t.~) Cu04"6 charged mod~l clust.ers in Ylg3 are the
HEOL
oharged model cluster of Cu(2) in the layer" and
-10
" [
-
1
I
- -
--
~
.
.
.
.
~I!_=
I I
--
I~
.
HEOL
10
.~,ii-=II
Cu(1) in the Ghain. It. is clear from the oxidation states that. the Cu atoms in a single c:hain of the -1/,
Y123 system act as electron donors Lo the Cu
illiIiIII
la 2 a ~ 6 a T a ~
,, w -
I-'',, I
-qg IbZb3b4bSb6bTbBb
at, om.~ in layers, l~e Cu at.(,m.~ in a double chain o f the Y124 system plays Ylg3 system
t h e same r n l e as in I:he
git,azawa s has d e f i n i t e l y shown t h a t
the o r i t lea l temI~,rature t,f s u p e m o n d u c l ~ s inorvases as the hole conceni:ratirm increases.
In
Fig. 1. Molee,u l a r o r b i t a l level diagrams f o r the oharged model c l u s t e r s l a .--~_ as tier.ermined by ASE[I-MO (; 1usteP ca l c u l a t i o n s .
Fig. 2. Molecular o r b i t a l level diagrams for t h e charged model c l u s t e r s !b--g.b as detern~ined by ASEI)-MO c l u s t e r ca I cu I at. tons.
the s t u b u i t h o u t point cha~ges, [.hehole of the Cu atom in the layer, and the c h a i n o f the YI?21 sysLem REFFPJSNCFN
is h i g h e r than iL is in the YI24 system. 'Fable I. The ( x i d a t i o n b t a t e and the Hole of Cu(1) and Cu(2) o f the YI23 and the Yl24 systems
I. M. A. Beno, t.. ~,derholm, D. W. Cat,me, l I , D. G. Hink~, J. D, dorgensen, J. l), Grace, and Ivan g. ~k:huller, C. /I. ~gr~. and K. Zhang, Appl. Phys. [ ~ t t . , 5I (1987) 57
~barged Model V N - - ] - h } i - d - a Y [ ; ; n - H;;]-o-- ] lUSl.er [ At.(Im | SlaLe " / YiZcVI c_'RGZ -6 . . . . l-e~C'_21I--!2_fi~o . . . . 0-,9~- l l- Cu0£ ~ - - T e - f f f f f J T - - 17Z_W!. . . . . . 6 . ~ . ~ d
2. P. Marsh, R. M. Fleming, M. L. Mandi(:h, A. }4. [~,.san(,olo, J. K~,, M. tfong and L. J. Mar%inez-Miranda, Nature, :.15.{4 (I988) I4I
['-CLiO.~_ . . . . . | - e U I C I 3 ] ~ - 71~6 ~6- . . . . . . .
0.-9"I-~--
-I
3. A. B. Anderson, J. Chem. Phys., 6g (1975) I187
g-¢i~oa_gga-rl c u ( D L L
L g~.1.~. . . .
.W~O_--1
/ Cu(2)]-- I,219 .......... ()~I87-_ ]
I cu_0i~E - - - T _ g ¢ l i 2 ? l 2-~ -foe . . . . .
0It0 I a Z ~
I Cu40i 4 - a - - ]-]~-u_-27!J~]-2{~O8---- LZ-gO_~1 _ _ [ -~ u_-(2~ -~.Ls_--g~ 70_7_b-gO7-]
I
.
ICu_OsH4- - ~ - - - f , O ~
_ _ _J . . . . . . . . . .
_~ c u _ . ~ ) . !
.
.
....
.
.
o ~i-~--1
Lal~__--L-_ Z.: L~_~I-I
Figm-e i and figure 2 shows the high-energy c~x;upied levet(HEOI,) in the oharged model c l u s t e r dashed-lines. gap between
4. X. H. Gao, Z. L. gin, H. gan,and X. I.. Wu, 5 ) l i d S t a t e Comm(micaLions, 76 (1990) 133
In figure. 1 and figus~. 2, the energy HOMO(Highest [kac;upied Molecular
O r b i t a l ) and I.[M}(t~c~e.st Un~×*~upied Molecular
5. Koichi l{itazawa, fIN J. RES. DEVEI,~)P., 33 (1988) 20i 6. Z. Zhi and Z. Ring-qi, S~,]id S t a t e Commun[cati,ms, 65 (I988) 5~9