Physical Review Letters
Editors:
JACK SANDWEISS
GEORGE BASBAS
STANLEY G. BROWN
REINHARDT B. SCHUHMANN
Associate Editors:
ROBERT GARISTO
BRANT M. JOHNSON
SAMINDRANATH MITRA
Re : LY10497
One-dimensional band-edge absorption in a doped quantum wire
by Toshyuki Ihara et al.
Dr. Toshiyuki Ihara
Inst. for Solid State Physics
(ISSP), University of Tokyo
Akiyama Group, Room A273
5-1-5 Kashiwanoha, Kashiwa
Chiba 277-8581, JAPAN
5 March 2007
Dear Dr. Ihara,
The above manuscript has been reviewed by our referee(s).
The resulting report(s) include a critique which we feel is ‘serious enough that it must be answered before we can reach a decision on the disposition of the paper. We enclose pertinent comments.
You may choose to resubmit the manuscript with revisions you find appropriate. With any resubmittal, please include a summary of changes and a brief response to all recommendations and criticisms.
Yours sincerely,
Samindranath Mitra
Associate Editor
Physical Review Letters
Report of Referee A – LY10497/Ihara
The authors describe the first observation of the band edge singularity induced by the 1D-DOS divergence. Experimental data of photoluminescence excitation spectroscopy (PLE) are discussed in conjunction with corresponding model calculations. For following reasons, the manuscript is not suitable for publication in Physical Review Letters:
1. The results of the current manuscript are not discussed in the context of former publications of the same group, e.g., proper citation to pertinent earlier work is not provided [e.g., APL 82, 379 (2003); APL 83, 2043 (2003); APL 86, 243101 (2005); APL 87, 223119 (2005)].
2. In the context of the above-mentioned former publications together with reference 10 of the considered manuscript, the current investigation appears rather as an extension of the former work than a step towards major advance on the corresponding subdiscipline. Moreover, a part of the results (band edge energy as a function of gate voltage derived from the PL spectra) has already been published in reference 10 in a similar way.
3. There is no convincing argument or prove for the assignments of the found transitions in the PL and PLE experiments. As an example, the reader is wondering why the PLE peak of Fig. 3 found at 0.2 V is assigned to a band edge transition, while a similar peak found at 0.15 V is assigned to trions.
4. The assignments of the exciton transitions contradict with the ones of the formerly published works and of the generally expected spectral position of excitons below the band gap energy. With this regard, any explanation is missing in the text and the reader is in doubt as to whether the given arguments are valid. Thus, the criterion of validity seems not to be satisfied.
Report of Referee B – LY10497/Ihara
This paper reports what is for me the first clean observation of PL and PLE in an indisputable isolated quantum wire (QWR). The experiments span the transition between excitonic and degenerate electron gas responses. No Fermi edge singularity (FES) is observed. This result is counterintuitive as FES have been observed in 2D and 3D systems and predicted in 1D. It is thus my belief that this paper constitutes a major and original contribution to the field of many-body interactions in reduced dimensions. I thus recommend publication in the Physical Review Letters once the following remarks have been addressed.
My main problem is with the discussion starting on the last paragraph of page 6. The authors affirm without proof that the PL and PLE peaks of Fig. 2 associated with X- for Vg<0.2 V suddenly becomes the band edge at – 0.3V. Why are they not simply the remnants of X-, coexisting with the Fermi edge? Is it not very surprising that a density of less than 1x10^5 cm-1, which corresponds to Ef much smaller that the binding energy of X-, be sufficient to wipe it out?
Other smaller points to address:
Page 4: “neglects many-body Coulomb interactions”. The word “neglects” is inappropriate. “does not take into account” or a similar expression would be less misleading.
Page 6, Fig. 2: the calculation shows a red shift of the BE with increasing temperature bigger than the experimental one. How was this shift calculated? Also, the authors should mention the photon energy of the laser for the PL measurements.
Last sentence, “made possible by … the development of a highly sensitive PLE system”: There is nothing extraordinary with the system and configuration described. For example, PL and PLE spectra of single quantum dots are routinely made nowadays.