求助

运行后报错：Undefined function or variable 'polt'.
Eg0=1.12;
a=4.73e-004;
b=636;
k0=8614e-005;
t1=10;
t2=600;
Ei=0;
n1=Ie+012;
n2=Ie+013;
n3=Ie+014;
n4=Ie+015;
n5=Ie+016;
n6=Ie+017;
n7=Ie+018;
mn=9.67e-031;
mp=5.37e-031;
h=1.054e-032;
k=1.380e-023;
n=[n1 n2 n3 n4 n5 n6 n7];
k0=8.614e-005
for j=1:1:7;
for i=t1:t2;
Eg=Eg0-(a*i^2)/(i+b);
Ec=Eg/2;
Ev=-Eg/2;
z=(mn*k*i)/(2*pi*h^2);
x=(mp*k*i)/(2*pi*h^2);
Nc=2*(z)^(3/2);
Nv=2*(x)^(3/2);
ni=sqrt(Nc*Nv)*exp(-Eg/(2*k0*i));
Efn=Ec+k0*i*log(N(j)/(2*Nc)*(1+sqrt(1+4*ni^2/N(j)^2)));
Efp=Ev-k0*i*log(N(j)/(2*Nc)*(1+sqrt(1+4*ni^2/N(j)^2)));
hold on
polt(i,Ei,i,Ec,i,Ev,i,Efn,i,Efp);
if Efn<=0
break
end
if Efp<=0
break
end
end
end