15.3 Cu 3 O 2 Model Reality
309
15.3 Cu 3 O 2 Model Reality
15.3.1 Numerical Quantification
The z 0 -optimizing method and the single-variable parameterized 3D-SPB functions
allow for further evaluation of the structure models in Fig. 15.2. The z 0 -optimizing
method duplicates the measured data and yields the corresponding structure- and
energy-dependent z 0 (E).
The program automatically fits the spectra by matching the computed I cal (E i )
to the experimental I exp (E i ) such that I cal (E i )/I exp (E i ) = 1.00 ± 0.03 at each step.
Figure 15.5 shows the calculation results for 43.5° and 48.5° azimuth angles. The
azimuths are selected such as these angles are far from affirmative insofar with
conventional approach.
Figure 15.5 shows that the z 0 -optimizing method makes all models work but different yields. Aside from the considerations and arguments insofar advanced for the
current M 2 O bond model A that is now further supported by the VLEED optimization. The structural models are selected by analyzing the z 0 (E) profiles. As given
in Table 15.2, the minimal value of z VLEED /z STM (43.5° curves provide maximal z) supports model A. The anisotropic z 0 (E) profiles suggest the essentiality
of introducing the non-uniform SPB. To this end, the improved method of singlevariable parameterization of the non-uniform SPB has been proven reliable and more
revealing than the conventional one-dimensional-SPB wise.
15.3.2 Physical Indication
15.3.2.1 The z 0 (E) Plots
A comparison of the z 0 (E) profiles can differentiate the structural sets of atomic positions (Fig. 15.5 and Table 15.2). All the considered crystal structures offer spectral
match near the <11> direction but the corresponding z 0 (E) curves are quitter different. This is right what one pursues. That the minor difference in atomic positions
results in the observable variation of the z 0 (E) profile evidences that the VLEED
is very sensitive to the crystal geometry. The bond geometrical dependence of the
z 0 (E) curve allows one to judge a model by simply comparing the shape of the z 0 (E)
profile with those of others.
One may assign the atomic-position (Table 15.2) as the one approaching to the true
situation by carefully analyzing the shape of the z 0 (E) curve against criteria given
in Sect. 15.1.4. From the perspective of energy, the z 0 (E) features below 7.5 eV
coincide with the STS and PES profiles showing the occupied DOS below E F on the
O-Cu(110) and O-Cu(001) surfaces, which has been attributed to the nonbonding
states, a characteristic of the sp
3 -orbital hybridization of oxygen. The sharp features
between 11.5 and 12.5 eV correspond to the Bragg reflections at the boundaries
309
15.3 Cu 3 O 2 Model Reality
15.3.1 Numerical Quantification
The z 0 -optimizing method and the single-variable parameterized 3D-SPB functions
allow for further evaluation of the structure models in Fig. 15.2. The z 0 -optimizing
method duplicates the measured data and yields the corresponding structure- and
energy-dependent z 0 (E).
The program automatically fits the spectra by matching the computed I cal (E i )
to the experimental I exp (E i ) such that I cal (E i )/I exp (E i ) = 1.00 ± 0.03 at each step.
Figure 15.5 shows the calculation results for 43.5° and 48.5° azimuth angles. The
azimuths are selected such as these angles are far from affirmative insofar with
conventional approach.
Figure 15.5 shows that the z 0 -optimizing method makes all models work but different yields. Aside from the considerations and arguments insofar advanced for the
current M 2 O bond model A that is now further supported by the VLEED optimization. The structural models are selected by analyzing the z 0 (E) profiles. As given
in Table 15.2, the minimal value of z VLEED /z STM (43.5° curves provide maximal z) supports model A. The anisotropic z 0 (E) profiles suggest the essentiality
of introducing the non-uniform SPB. To this end, the improved method of singlevariable parameterization of the non-uniform SPB has been proven reliable and more
revealing than the conventional one-dimensional-SPB wise.
15.3.2 Physical Indication
15.3.2.1 The z 0 (E) Plots
A comparison of the z 0 (E) profiles can differentiate the structural sets of atomic positions (Fig. 15.5 and Table 15.2). All the considered crystal structures offer spectral
match near the <11> direction but the corresponding z 0 (E) curves are quitter different. This is right what one pursues. That the minor difference in atomic positions
results in the observable variation of the z 0 (E) profile evidences that the VLEED
is very sensitive to the crystal geometry. The bond geometrical dependence of the
z 0 (E) curve allows one to judge a model by simply comparing the shape of the z 0 (E)
profile with those of others.
One may assign the atomic-position (Table 15.2) as the one approaching to the true
situation by carefully analyzing the shape of the z 0 (E) curve against criteria given
in Sect. 15.1.4. From the perspective of energy, the z 0 (E) features below 7.5 eV
coincide with the STS and PES profiles showing the occupied DOS below E F on the
O-Cu(110) and O-Cu(001) surfaces, which has been attributed to the nonbonding
states, a characteristic of the sp
3 -orbital hybridization of oxygen. The sharp features
between 11.5 and 12.5 eV correspond to the Bragg reflections at the boundaries