Electronic Structures and Magnetic Properties of Co/Mn Co-Doped ZnO Nanowire: First-Principles LDA+U Studies

Round 1

Reviewer 1 Report

REVIEWER’S COMMENTS

Electronic structures and magnetic properties of Co/Mn codoped ZnO nanowire: First-principles GGA+U studies

            The authors investigated the electronic structure and magnetic properties of Co/Mn co-doped ZnO nanowires using a first-principles calculation method based on density functional theory (DFT) in conjunction with LDA+U schemes, and systematically discussed the optimal geometric replacement position, coupling mechanism, and magnetic origin of Co/Mn atoms. They have also observed that all configurations of Co/Mn co-doped ZnO nanowires exhibit ferromagnetism, and the system is in the ground state when Co/Mn replaces the Zn atom in the inner layer of ZnO nanowires along the [0001] direction. The calculated findings indicate that the magnetic moment is mostly derived from Mn/Co 3d orbital electrons and that the magnetic moment size is related to the electronic configurations of Mn/Co atoms. LDA+U describes the electrical structure of Co/Mn co-doped ZnO nanowires is also observed. According to these findings, authors claim that Co/Mn co-doped ZnO nanowires would be a viable choice for diluting magnetic semiconductor materials.

Specific Comments:

            Improvement concerning the theoretical depth in the introduction and discussion sections may benefit from more extensive explanations. The authors have explained with much literature in the introduction part is found to be good. Yet the necessity for the current study, and how the scientific relevance could be improved. The work's uniqueness, as well as the extent of its applicability, must be described. The abstract needs to be revised since it lacks accuracy, technical and scientific facts, and a complete overview. The manuscript can be improved overall considering the major comments given below.

Major Comments:

·      The Introduction part should be accurate and clear, with extensive research background relevant to his study. The manuscript's language and flow of information could be improved, and a more comprehensive summary of the findings should be included.

·      The manuscript should be checked for grammatical errors.

·      The manuscript includes non-technical terms which can be corrected.    
Example:

    1. ‘The paper’ can be corrected as the research findings or previous/present work

    2. The term controversy can be replaced.   

·      Explain ‘high Tc ZnO nanomaterials’. What does Tc represent here?

·      Detailed information and explanation about the theoretical model should be given. What is the source of the establishment of these models?

·      Authors should explain the detailed calculation and reasons for selecting this particular software.

·      Details about AFM and FM coupling have not been observed.

·      How the authors do confirms that O atoms include both FM and AFM. 

·      What do the authors arrive at from this statement ‘we can approximately deem that the Co and Mn atoms are in the crystalline field (Td) of the tetrahedron’?

·      The arrived results are not well discussed.

·      How do the authors validate the results Co/Mn co-doped ZnO is a good candidate for obtaining room-temperature ferromagnetism?

·      The results are insufficient and no proper inferences have been made.

·      The manuscript lacks technical and scientific details.

·      In the conclusion section, no proper conclusions are made. The summary of the work has not been explained.

Overall, the article lacks sufficient validations, homogeneity, scientific foundation, and acceptance justifications. 

 

 

Author Response

Dear editor and Reviewer：

    Thank you very much for giving us an opportunity revising this manuscript, we appreciate editor and reviewers very much for their positive and constructive comments and suggestions on our manuscript entitled “Electronic structures and magnetic properties of Co/Mn codoped ZnO nanowire: First-principles GGA+U studies”. We have studied reviewer’s comments carefully and the paper was revised according to the referees’ comments.

Author Response File: Author Response.docx

Reviewer 2 Report

This paper examines the possibility of magnetic coupling between Co and Mn when doped in ZnO nanowires. Achieving room temperature ferromagnetism in ZnO has been sought for the last 20 years, as ZnO is environmentally benign and cheap. The novelty in this manuscript lies in the examination of magnetic coupling in one-dimensional systems. However, before this manuscript can be accepted for publication, the following shortcomings must be addressed:

Were the six doping configurations exhaustive considering symmetry? If not, what was the rationale for excluding some?

A justification, either based on the authors’ examination or examples from the literature, should be provided for the choice of +U values.

Additional important information on the DFT parameters should be provided: How fine was the fast Fourier transform mesh? What type of electronic minimization algorithm was used? Was there any smearing as well? What were the thresholds for energy and force for geometry optimization? Was there any symmetry restriction?

It needs to be readily evident in Fig. 2 if, along the [0001] direction, the periodic boundary conditions have been applied. A cross-sectional view is appreciated.

Given the maturity of this field, some important references are missing: The seminal review on the DFT methods in diluted magnetic semiconductors research, which outlines the validity of the methods and interpretations used in this article: Sato et al. Rev. Mod. Phys. 82, 1633 (2010) https://doi.org/10.1103/RevModPhys.82.1633; Also, this early reference that indicates the feasibility of Mn and Co as dopants in ZnO with long range and room temperature ferromagnetic coupling: Assadi et al. J. Appl. Phys. 111, 113901 (2012) https://doi.org/10.1063/1.4719977.

Author Response

Dear editor and Reviewer：

    Thank you very much for giving us an opportunity revising this manuscript, we appreciate editor and reviewers very much for their positive and constructive comments and suggestions on our manuscript entitled “Electronic structures and magnetic properties of Co/Mn codoped ZnO nanowire: First-principles GGA+U studies”. We have studied reviewer’s comments carefully and the paper was revised according to the referees’ comments.

Author Response File: Author Response.docx

Reviewer 3 Report

Manuscript Number: coatings-2092094

Electronic structures and magnetic properties of Co/Mn codoped ZnO nanowire: First-principles GGA+U studies.

Authors: Suqin Xue*, Lei Zhang, Gaihui Liu, Qiao Wu, Jing Ning, Bohang Zhang, Shenbo Yangshenbo, Fuchun Zhang*, Weibin Zhang*.

In general, I have completed my evaluation of your manuscript. I encourage the acceptance of this paper after the incorporation of all comments as a major revision. I invite you to resubmit your manuscript after addressing the comments below.

Coatings Journal

Due date: 23 December 2022

Comments to authors

1. The formatting of the references is not good. Sometimes they wrote the abbreviation before the name and sometimes they wrote it after the name also, they wrote the title of the article and sometimes not: for example “[9] Liu, R.; B.; Shi, L.; J.; Zou, B.; S. Magnetic exciton relaxation and spin-spin interaction by the time-delayed photoluminescence spectra of ZnO: Mn nanowires. Appl. Mater. Interfaces 2014, 6, 10353−10366. [10] Chang, L.; Wang, T.; C.; Y.; Tang, J.; S.; Nie, T.; X.; Jiang,W.; J.; Chu,C.; P.; Arafin, S.; He, L.; Afsal, M.; Chen, L.; J.; Wang, K.; L. Electric-field control of ferromagnetism in Mn-doped ZnO nanowires. Nano Lett. 2014, 14, 1823−1829.”. The authors should be revised the references according to the rules of the Coatings journal.   

2- The level of English throughout your manuscript should be improved for examples:

- In introduction section; the first sentence, “Diluted magnetic semiconductors (DMSs) are a new type of semiconductor materials which obtains ferromagnetism by doping transition metal (TM)” should be replaced by “Diluted magnetic semiconductors (DMSs) are a new type of semiconductor material that obtains ferromagnetism by doping transition metal (TM) in it.”

- “It has found key applications in high-density nonvolatile memories, magnetic sensors, spin field effect transistors, optical isolators, semiconductor lasers and other fields,……..” should be replaced by “It has found key applications in high-density nonvolatile memories, magnetic sensors, spin field effect transistors, optical isolators, semiconductor lasers, and other fields,……..”.

- “In particular, oxide-diluted magnetic semiconductor (ODMS) is considered as the main material for fabricating microelectronic devices using electron spin degrees of freedom, and…….” should be replaced by “In particular, oxide-diluted magnetic semiconductor (ODMS) is considered the main material for fabricating microelectronic devices using electron spin degrees of freedom and…….”.

Please, revised the English in whole manuscript.

3- In the whole manuscript the authors sometimes wrote Figure and sometimes wrote Fig. as in so, the authors should to be consistent?

4- Comparative studies on related results should be presented, to illustrate the interest of this work.

5- In Fig. 1 and 2. The images with high resolution should be provided.

6- In the last paragraph in “Introduction” section; the authors mentioned that “Tc ZnO nano materials. What do you mean by “Tc”.

7- The legends in Figures 3 and 5 are not clear. Please, provide images with high resolution.

8- In “3.2 Magnetic properties” section; “The energy level of TM atom in the tetrahedron will be split into a three degree of degeneracy t2g  state (dxy, dyz, dxz) and a two degree of degeneracy eg  state ( 2 2 z r d - , 2 2 x y d - ).”  There are some distances in this section should be deleted.  

 

9- In Figure what is the difference between the anti-bonding state and non-bonding state?

Comments for author File: Comments.pdf

Author Response

Dear editor and Reviewer：

    Thank you very much for giving us an opportunity revising this manuscript, we appreciate editor and reviewers very much for their positive and constructive comments and suggestions on our manuscript entitled “Electronic structures and magnetic properties of Co/Mn codoped ZnO nanowire: First-principles GGA+U studies”. We have studied reviewer’s comments carefully and the paper was revised according to the referees’ comments.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

The quality of the manuscript have been improved a lot after the review. All the comments have been well answered/rebutted by the authors. I recommend to accept the manuscript in the revised form.   

Reviewer 2 Report

The authors have satisfactorily revised their manuscript.

Reviewer 3 Report

Manuscript Number: Coatings-2092094

 

Electronic structures and magnetic properties of Co/Mn Co-doped ZnO nanowire: First-principles LDA+U studies.

 

SuqinXue¹, Lei Zhang¹, Gaihui Liu¹, QiaoWu¹, Jing Ning¹, Bohang Zhang¹, Shenbo Yang³, Fuchun Zhang^1*, WeibinZhang^2*.

 

Thanks so much for giving me the opportunity to review this manuscript in such a highly qualified journal of Coatings.

 

In general, I have completed my evaluation of the revised manuscript. I considered that the authors done all the comments points by points to the fullest and I recommend accepting this article to publish in Coatings Journal.