How can i find parameter in loops according to calculation result ？

Here is my code

syms E Eg V g;
z=[ ];
y=[ ];

c=3 .*(10.^8); 
h=4.1361e-015; 
k=8.62E-5;
Tc=300;

for Ei=0.5:.05:0.6
z=[ ];
for Eg=1.4:0.01:1.75;

Ec=Eg-Ei;
a = quad( @(E)(E.^2) ./ (exp(E./0.5172)-1), Eg , 100);
aa= quad( @(E)(E.^2) ./ (exp(E./0.5172)-1), Ec , Eg);

for Ucv=Eg-.2:.005:Eg-.01;
    b = quad(@(E)(E.^2) ./ (exp(( E-Ucv )./0.0259)-1),Eg,100);

for Uiv=Ei-.1:.005:Ei-.01;

      Uci=Ucv-Uiv;
  Pin=(2.*pi().^5.*(k.*6000).^4)./(15.*h.^3.*c.^2) ;  % SQ_model;                                                        

bb= quad(@(E)(E.^2) ./ (exp(( E-Uci )./0.0259)-1),Ec,Eg);

if abs(quad( @(E)(E.^2) ./ (exp(E./0.5172)-1), Ei , Ec)- quad(@(E)(E.^2) ./ (exp(( E-Uiv )./0.0259)-1),Ei,Ec)-...
        aa+bb)  <=  10^-4

P = ( 2.*pi().*Ucv./6.3682e-027 ) .* ( a + aa - b - bb ) ./ Pin  ;

z = [z P]  
m = max(z) 
  end

end
end
end
y=[y m]
end

result is

y =

      0.6025    0.6137    0.6241

I want to get Ei,Eg,Ucv and Uiv which parameter in loops calculate result y is 0.6137 .

thank you :)