{"id":"6b76d7a0-2f13-4ad0-abce-48a71bcbb3d9","arxiv_id":"2507.11309","paper_version":1,"verdict":"CONDITIONAL","confidence":"HIGH","novelty_score":7.0,"correctness_risk":"medium","formal_verification":"none","parameter_count":6,"one_line_summary":"The supramolecular material FCH-C3-A is a ferroelectric with two dipolar sublattices, each switching at its own coercive field, and its conductivity depends on the polarization state.","lead":"A molecular material with two different electric-dipole building blocks flips its polarization in two separate steps and changes its electrical conductivity depending on the polarization direction. This combination of switchable dipoles and tunable conduction points toward organic ferroelectrics that could act as memory and switch in one material.","discovery_kind":"first_principles","skeptic_critique":{"model":"deepseek-v4-flash","headline":"The two-sublattice interpretation is underdetermined: double coercive features could come from two switching populations in a single structural phase, and the FCH-E control changes more than the amide group.","rationale":"The reader's verdict is CONDITIONAL, and my independent read converges on the same weakest point. The paper's strongest claim inherits the unsupported step 'spatially separated sub-stacks' (Fig. 1f), which is a structural assertion, not a logical consequence of the electrical measurements. The alternative of two switching populations within a single phase is plausible, and the FCH-E comparison is confounded by the C3 linker and by the loss of long-range fiber formation. However, this does not undermine the other supported claims: the CV butterfly loops indicate genuine small-signal ferroelectric-like response, the TA-NLS analysis of peak shifts is consistent, KPFM directly shows field-induced interfacial dipoles, and the correlation between depolarization and current modulation supports a causal link. These are independent of the sublattice decomposition. Therefore the appropriate verdict remains CONDITIONAL: accept ferroelectricity and polarization-dependent conductivity as plausible, but require structural evidence or a properly matched control before the two-sublattice interpretation is promoted from hypothesis to established claim. No change to the reader's verdict is needed.","tokens_in":19863,"tokens_out":8638,"duration_ms":112432,"concrete_test":"Measure DWM and CV on a control compound identical to FCH-C3-A except that the amide group is replaced by a weakly polar isostere that preserves the C3 linker and the fiber-forming self-assembly. Record the 70 °C DSC feature, the low-field CV peak, and the low-field DWM shoulder under the same protocol (110 °C, 10-25 mHz, on interdigitated electrodes). If all three persist while fiber formation is retained, the low-E process is not the amide sublattice and the two-sublattice central claim fails; if they vanish while fiber formation remains, the assignment is confirmed. This control isolates the amide dipole without the confounding C3-linker and morphology differences present in FCH-E.","verdict_should_be":"UNCHANGED","load_bearing_attack":"The central claim that FCH-C3-A contains two spatially separated ferroelectric sublattices made of amide and FCH stacks rests on the double peaks in CV/DWM, the assignment of the low-field peak to the amide via FCH-E, and the structural sketch in Fig. 1f. The sketch is explicitly a 'possible orientation,' and no GIWAXS, electron diffraction, or high-resolution AFM data in the paper resolves separate amide and FCH sub-stacks in the fibers. The double butterfly peaks in Fig. 3 and the two DWM shoulders in Fig. S3/S6 are equally compatible with two switching populations inside a single structural phase (e.g., differently oriented domains or near-electrode vs. bulk regions), an alternative the authors themselves invoke for PZT in ref. 45. The control molecule FCH-E (Fig. 1b) removes the amide but also changes the C3 linker and the ester connectivity and does not form long-range fibers (Fig. S7), so its missing 70 °C DSC feature and missing low-field peak do not uniquely identify the amide as the low-E sublattice. The SI further notes that the DWM peaks are 'conductivity peaks and not switching peaks,' which complicates using DWM peak positions as direct proof of two independent polarization reversals. Thus the 'two sublattices' claim is not structurally established, even though ferroelectricity and polarization-modulated conductivity have independent support.","agreement_with_reader":"agree"},"referee_report":{"model":"deepseek-v4-flash","summary":"The paper reports ferroelectricity and polarization-dependent conductivity in a supramolecular small-molecule material, FCH-C3-A, which contains two dipolar moieties: an all-cis fluorinated cyclohexane ring and an amide group. The authors interpret double coercive features in double-wave-method (DWM) and capacitance-voltage (CV) measurements as evidence for two independent ferroelectric sublattices formed by spatially separated stacks of these moieties, and assign the low-field and high-field peaks to the amide and FCH groups respectively using a reference compound FCH-E. They further demonstrate that the conductivity is modulated by the polarization state, with injection-barrier modulation at low fields and bulk-conductivity switching at high fields, supported by in-operando KPFM and zig-zag pulse measurements. The material is proposed as a promising multifunctional organic ferroelectric.","tokens_in":20256,"tokens_out":5171,"duration_ms":55374,"significance":"If fully established, the two-sublattice feature would be a notable novelty for organic ferroelectrics, and the demonstration of polarization-modulated conductivity in a non-pi-conjugated molecular material extends previously reported mechanisms from semiconducting organic ferroelectrics to a broader class. The manuscript contains extensive experimental characterization, including DWM, CV, DSC, dielectric spectroscopy, KPFM, and TA-NLS analysis, and it carefully discusses the influence of conductivity on the apparent polarization loops. However, the central two-sublattice claim is structurally underdetermined: the spatial separation of the two dipole stacks is inferred rather than directly observed, and the control molecule used for peak assignment differs from FCH-C3-A in more than just the amide group. Ferroelectricity and polarization-modulated conductivity have independent support, but the specific two-sublattice interpretation requires either stronger structural evidence or an appropriately softened formulation.","major_comments":[{"comment":"The two-sublattice interpretation rests on the assumption that the two dipolar moieties form spatially separated sub-stacks within the supramolecular fibers. The text states this is a 'possible orientation' and that the moieties are 'assumed' to form spatially separated sub-stacks; no GIWAXS, electron diffraction, or high-resolution AFM data in the main text or SI resolve separate FCH and amide sub-stacks inside the fibers. The double butterfly peaks in Fig. 3 and the two shoulders in DWM (Figs. S3, S6) are equally compatible with two switching populations within a single structural phase, such as differently oriented domains or near-electrode versus bulk regions, an alternative the authors themselves invoke for PZT via ref. 45. Please provide direct structural evidence for sub-stack separation, or reformulate the central claim as an interpretation consistent with the data rather than an established structural fact.","section":"Results and Discussion, Fig. 1f and text"},{"comment":"The assignment of the low-field peak to the amide group uses FCH-E as a control, but FCH-E differs from FCH-C3-A by more than just the amide: it also lacks the C3 linker and, as the authors note, does not form long-range supramolecular structures (Fig. S7, S8). The absence of the low-field peak and the missing 70 °C DSC feature in FCH-E therefore do not uniquely identify the amide as the low-E sublattice; the differences could stem from altered molecular packing or mobility rather than from the removal of the amide dipole. A more selective control (e.g., a derivative with the amide but no FCH, or an N-alkylated amide) or direct structural/spectroscopic assignment is needed to support the peak-to-moiety mapping.","section":"Results and Discussion, FCH-E control (Fig. 4)"},{"comment":"The SI states that 'the peaks in the DWM are conductivity peaks and not switching peaks.' This is critical because the paper uses DWM peak positions to extract coercive fields and to infer two separate switching events. If the DWM peaks are conductivity-modulated, the two-peak structure in DWM could arise from the same conductivity mechanisms (IBM/BCS) rather than from two independent polarization reversals. The CV butterfly loops are more direct evidence for ferroelectric switching, but the text does not explicitly quantify how much the conductivity background shifts or distorts the DWM-derived coercive fields. Please clarify which observations are unambiguous polarization-switching signatures and how the conductivity background affects the DWM peak interpretation.","section":"SI Fig. S3 note and main text (Figs. 2, 3)"},{"comment":"The TA-NLS fits fix the polarization values to the theoretical values of the individual moieties (31 and 52 mC/m² in Fig. S3e; 69 mC/m² for FCH-E in Fig. S9d). The agreement between fit parameters for the FCH-C3-A high-field peak and FCH-E is then used as evidence for peak assignment. This reasoning is partially circular because the same theoretical polarization enters both the assignment and the fit. While the CV data provide independent support, the paper should explicitly state that the TA-NLS fits alone cannot validate the two-sublattice assignment.","section":"SI Eq. 1 and Figs. S2, S3, S11"}],"minor_comments":[{"comment":"The name 'Vasalek' in the first sentence should be 'Valasek'; the SI also contains a typo in 'Kalmogorov-Avrami-Ishibashi', which should be 'Kolmogorov'.","section":"Introduction"},{"comment":"The dipole is described as an 'all-cis 1,2,3,4,5,6-hexafluorocyclohexane unit' in the abstract and main text, but the SI name is '(1r,2R,3R,4s,5S,6S)-2,3,4,5,6-pentafluorocyclohexyl' and a later passage says 'all-cis pentafluorocyclohexane group'; please make the nomenclature consistent.","section":"Abstract and main text vs. SI"},{"comment":"Reference 48 is a duplicate of reference 27; please consolidate.","section":"References"},{"comment":"The inset shows the reversible polarization with a scale of ±0.23 mC/m², but the text does not explain this value; a sentence would help the reader.","section":"Fig. 2b"}],"recommendation":"major_revision","confidential_remarks":"The manuscript is within scope for cond-mat.mtrl-sci. The two-sublattice claim is the most novel aspect, but it currently rests on an inferred structural model and a confounded control; a revision that adds direct structural evidence or tempers the claim to 'two switching populations' would make it publishable. The ferroelectricity and conductivity-modulation parts are well supported and should be highlighted as strengths."},"author_rebuttal":null,"desk_editor":{"model":"deepseek-v4-flash","letter":"First thing to know: this is a genuinely useful experimental paper. The authors show, with DWM, CV butterfly loops, TA-NLS fits, and a reasonable control molecule, that FCH-C3-A is ferroelectric and that its conductivity is modulated by polarization, including in a material without an extended pi-system. The observation of two distinct coercive fields in both CV and DWM is new and is the paper's real contribution.\n\nWhat the paper does well: the electrical characterization is careful about the awkward geometry (in-plane IDEs, rough films) and the authors are transparent that quantitative polarization values are approximate. The zig-zag conductivity measurements plus KPFM give independent lines of evidence for the conductivity modulation, and the low-field IBM / high-field BCS interpretation is plausible. The TA-NLS fits are used responsibly, with theoretical polarization values fixed rather than fit. The comparison to FCH-E is a sensible attempt to assign peaks.\n\nNow the soft spots, in proportion. The central claim about two spatially separated ferroelectric sublattices is underdetermined. The structural sketch in Fig. 1f is explicitly a 'possible orientation,' and no GIWAXS, electron diffraction, or high-resolution AFM resolves separate amide and FCH sub-stacks in the fibers. Double peaks in CV and DWM are equally compatible with two switching populations inside a single structural phase—the PZT analogy with 90/180 domains is itself a counterexample to the authors' preferred reading. The control FCH-E also changes the C3 linker and ester connectivity and does not form long-range fibers, so its missing low-field peak does not uniquely finger the amide. More importantly, the SI states that the DWM peaks are 'conductivity peaks and not switching peaks'; that weakens the use of DWM peak positions as direct proof of two independent polarization reversals, though the CV data provide cleaner evidence.\n\nWhere does this leave the paper? The ferroelectricity and the polarization-dependent conductivity are well supported. The two-sublattice interpretation is a reasonable hypothesis, but it is presented as a conclusion. That distinction matters because the novelty claim ('first organic ferroelectric with two independent switchable sublattices') hangs on it. This is fixable with softer framing in the abstract and title, or stronger structural evidence.\n\nMy take: this deserves a serious referee. It is not a desk reject. The experiments are reproducible in principle, the analysis is mostly careful, and the two-coercive-field observation plus conductivity modulation will be of real interest to the organic ferroelectrics community. If I were the editor I would send it to review with the explicit instruction that the two-sublattice assignment needs either direct structural support or appropriate hedging. I would cite the paper for the experimental phenomenology.","headline":"Solid experimental work on a supramolecular ferroelectric with two distinct switching thresholds and polarization-modulated conductivity; the 'two sublattices' structural claim is plausible but unproven.","tokens_in":20812,"tokens_out":2248,"would_cite":true,"duration_ms":24596,"reading_group":"yes","serious_thinker":"yes","would_accept_peer_review":true},"rs_alignment":null,"lean_confirmation":null,"pith_extraction":{"msc":[],"pacs":[],"model":"deepseek-v4-flash","headline":"A supramolecular fiber of the small molecule FCH-C3-A is a true ferroelectric with two independent dipolar sublattices that switch at distinct coercive fields, and its electrical conductivity is controlled by polarization direction and…","keywords":["organic ferroelectrics","supramolecular polymers","two ferroelectric sublattices","coercive field","polarization-dependent conductivity","injection barrier modulation","bulk conductivity switching","double-wave method"],"falsifier":"A structural determination of annealed FCH-C3-A fibers, for example by cryo-electron microscopy or grazing-incidence diffraction with selective labelling, that showed the amide and fluorinated cyclohexane groups interdigitated in the same column rather than segregated into separate sub-stacks would falsify the two-sublattice interpretation; so would a single-dipole derivative containing the amide but no fluorinated ring that still displayed two switching peaks.","tokens_in":19639,"feed_emoji":"⚡","tokens_out":9991,"duration_ms":111931,"temperature":0.7,"pith_summary":"This paper reports that the small molecule FCH-C3-A, which self-assembles into supramolecular fibers, is a genuine organic ferroelectric whose polarization is carried by two largely independent dipolar groups: an amide and an all-cis fluorinated cyclohexane ring. In polarization-switching and capacitance-voltage measurements the two groups show up as two separate coercive fields, roughly 2.8 and 9.8 V/µm at 110 °C, so the material behaves as if it contained two ferroelectric sublattices in one film. The same material conducts electricity without a conjugated π-system, and the direction and degree of polarization modulate that conductivity, by injection barrier changes at low fields and by bulk hopping-conductivity switching at high fields. If these claims hold, a single molecular film can combine switchable polarization states with polarization-controlled conductance, a combination relevant for memory and multifunctional devices.","feed_headline":"Two dipole halves switch at separate fields in one organic ferroelectric","feed_subtitle":"The same supramolecular film conducts electricity, and polarization direction tunes that conductance.","key_machinery":"The load-bearing object is the molecular architecture of FCH-C3-A: an all-cis fluorinated cyclohexane ring with a dipole of roughly 6.2 D and an amide group with a dipole of roughly 3.7 D, joined by a three-carbon spacer, which in the solid state organizes into supramolecular fibers whose stacks are assumed to segregate the two dipoles into spatially separated sub-columns. This arrangement yields two partially independent switching populations with separate coercive fields. The measurement machinery is the double-wave method and capacitance-voltage butterfly loops, and the interpretation machinery is thermally activated nucleation-limited switching (TA-NLS), used to fit the temperature and frequency dependence of both coercive fields, plus injection-barrier modulation and asymmetric polaron-hopping models for the conductivity response.","core_discovery":"The central claim is that thin films of the small molecule FCH-C3-A are ferroelectric, not through one switchable polarization but through two largely independent dipolar moieties that act as separate ferroelectric sublattices. Double-wave method current transients show two distinct switching peaks, and capacitance-voltage sweeps show a double-peaked butterfly loop, with coercive fields of roughly 2.8 and 9.8 V/µm at 110 °C. By comparing with the amide-free derivative FCH-E, which switches at fields matching the high-field peak and lacks the low-field feature, the authors assign the low-field peak to the amide group and the high-field peak to the all-cis fluorinated cyclohexane ring. The same material, though lacking a π-electron system, conducts electricity by successive oxidation and reduction with electron hopping, and this conductance is modulated by ferroelectric polarization: at low fields the polarization changes the injection barrier at the electrodes, while at high fields it biases the bulk hopping conductivity, with on/off current ratios of roughly 2–5 extracted from switching-current slopes.","pith_inferences":["Editorial inference: if the two-sublattice picture is right, FCH-C3-A should support at least three remanent polarization levels by poling between the two coercive fields, making it a candidate for multi-level or analog memory in a single molecular film.","Editorial inference: the peak assignment would be cleaner with a derivative that removes only the fluorinated cyclohexane dipole while retaining the amide and C3 linker, since FCH-E changes two structural variables and supramolecular ordering at once.","Editorial inference: the same polarization-modulated hopping mechanism could generalize to any molecular solid with aligned permanent dipoles and weakly redox-active sites, not just this molecule.","Editorial inference: the tentative field-dependent Curie-temperature explanation for the small reverse-sweep CV peak implies the second sublattice might become paraelectric-like at high fields, which temperature-dependent CV at fixed field could test."],"forward_implications":["The material offers a single-component organic film whose ferroelectric polarization state can be read out through, or used to control, its electrical conductance without needing an extended π-conjugated system.","Because the two sublattices switch at different fields, partial poling between the two coercive fields should leave one sublattice flipped and the other not, making intermediate polarization states physically accessible.","The strong polarization-dependent conductivity means integrated double-wave-method current overestimates the true ferroelectric polarization; coercive fields from peak positions remain meaningful, while loop-derived polarization magnitudes are apparent values.","The transfer of two-coercive-field behavior, previously known in PZT ceramics, to a supramolecular molecular ferroelectric opens a soft, solution-processable analogue with comparable multi-feature switching."],"supporting_citations":[{"why":"Provides the prior demonstration of long-range electronic conductivity in non-π-conjugated FCH-C3-A, the roughly 1.7 eV injection barrier estimate, and evidence excluding mobile ions and degradation; also identifies FCH-E as an insulator without long-range supramolecular order.","marker":"25"},{"why":"Shows FCH-C3-A undergoes living supramolecular polymerization into double helices transferable to solid films, the basis for the fiber and sub-stack structural model.","marker":"32"},{"why":"Supplies the double-wave method used to extract switching currents and separate them from leakage and displacement backgrounds.","marker":"37"},{"why":"Supplies the thermally activated nucleation-limited switching (TA-NLS) model used to fit the temperature and frequency dependence of each coercive field.","marker":"40"},{"why":"Raises the leaky-dielectric alternative that can mimic ferroelectric hysteresis loops, the counter-hypothesis the authors must exclude.","marker":"44"},{"why":"Provides the precedent of double-peak butterfly capacitance-voltage loops, attributed to domains with different coercive fields in PZT.","marker":"45"},{"why":"Demonstrates coexistence of injection-barrier modulation and bulk conductivity switching in an organic supramolecular semiconducting ferroelectric, the framework used to interpret the modulation sign change.","marker":"21"},{"why":"Establishes a switchable charge injection barrier at organic ferroelectric/metal interfaces, which underpins the low-field injection-barrier-modulation assignment.","marker":"26"},{"why":"Provides the ferroelectric self-assembled materials showing rectifying and switchable conductivity, the basis for the bulk conductivity switching (asymmetric polaron hopping) interpretation at high fields.","marker":"27"},{"why":"Expands the theory of nonlinear conductivity switching in semiconducting organic ferroelectrics using molecular dynamics and density functional theory, supporting the high-field bulk switching interpretation.","marker":"29"}],"fun_headline_variants":["Double switching and tunable conduction in one organic film","Ferroelectric with two independent switchable dipoles","Polarization tunes conductivity in two-sublattice ferroelectric","Two coercive fields, one molecular ferroelectric"],"cache_read_input_tokens":3200,"weakest_assumption_plain":"The load-bearing premise is that the two dipolar groups are physically segregated into separate sub-stacks within each supramolecular fiber, so each can switch as an independent ferroelectric sublattice; the double switching peaks could instead come from two switching populations within a single structural phase, and the amide-free control molecule differs from FCH-C3-A in more ways than just the missing amide.","fun_headline_variants_meta":{"raw":{"variants":["Double switching and tunable conduction in one organic film","Ferroelectric with two independent switchable dipoles","Polarization tunes conductivity in two-sublattice ferroelectric","Two coercive fields, one molecular ferroelectric"]},"model":"deepseek-v4-flash","effort":"low","cost_usd":0.000259,"raw_usage":{"total_tokens":1581,"prompt_tokens":935,"completion_tokens":646,"prompt_tokens_details":{"cached_tokens":384},"prompt_cache_hit_tokens":384,"prompt_cache_miss_tokens":551,"completion_tokens_details":{"reasoning_tokens":580}},"tokens_in":551,"tokens_out":646,"duration_ms":7379,"temperature":1.0,"reasoning_tokens":580,"cache_read_input_tokens":384,"cache_creation_input_tokens":0},"cache_creation_input_tokens":0},"created_at":"2026-08-06T17:11:40.295193+00:00","model_set":{"reader":"deepseek-v4-flash"},"falsifier":"A structural determination of annealed FCH-C3-A fibers, for example by cryo-electron microscopy or grazing-incidence diffraction with selective labelling, that showed the amide and fluorinated cyclohexane groups interdigitated in the same column rather than segregated into separate sub-stacks would falsify the two-sublattice interpretation; so would a single-dipole derivative containing the amide but no fluorinated ring that still displayed two switching peaks.","supporting_citations":[],"review_version":1}