Power spectral density : it is right to evaluate with this script?

Hi! I want to evaluate the power spectral density of my signal after fft. Do you think it is right to procede in this way:

Y11 = fft(Y)*delta_t;
M = length(Y);
Y22 = fftshift(Y11);
f11 = (-M/2:M/2-1)/(M*delta_t);

figure(12)
hold on 
grid on
plot(f11, abs(Y22).^2);
legend("output power spectral density")
xlabel("f");