SciPost Submission Page
Electron charge dynamics and charge separation: A response theory approach
by Lionel Lacombe, Lucia Reining, Vitaly Gorelov
Submission summary
| Authors (as registered SciPost users): | Vitaly Gorelov |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202512_00029v1 (pdf) |
| Date submitted: | Dec. 11, 2025, 4:11 a.m. |
| Submitted by: | Vitaly Gorelov |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approaches: | Theoretical, Computational |
Abstract
This study applies response theory to investigate electron charge dynamics, with a particular focus on charge separation. We analytically assess the strengths and limitations of linear and quadratic response theories in describing charge density and current, illustrated by a model that simulates charge transfer systems. While linear response accurately captures optical properties, the quadratic response contains the minimal ingredients required to describe charge dynamics and separation. Notably, it closely matches exact time propagation results in some regime that we identify. We propose and test several approximations to the quadratic response and explore the influence of higher-order terms and the effect of on-site and nearest-neighbour interactions $U$ and $V$.
Author indications on fulfilling journal expectations
- Provide a novel and synergetic link between different research areas.
- Open a new pathway in an existing or a new research direction, with clear potential for multi-pronged follow-up work
- Detail a groundbreaking theoretical/experimental/computational discovery
- Present a breakthrough on a previously-identified and long-standing research stumbling block
Author comments upon resubmission
List of changes
Line 52: change “optical” to “spectral”
Line 157: add “spatial extensions"
Line 148-149, Eqs. 7-12, and throughout the text: introduced A^n and A^j
Line 180: Add “and can never be longer than the inverse of the gap”
Eqs. 13-19 and throughout the text: introduce B^n and B^j
Line 308: add a paragraph “The choice of the model has to be a minimal yet comprehensive … ”
Line 326: add the description of the Hamiltonian “were $\hat c_{\alpha i}$ ($\hat c_{\alpha i}^{\dagger}$) annihilates (creates)... ”
Change Fig.3 (left and middle panels) and its legend
Line 375: Removed “Here and throughout the manuscript…”
Line 377: Add “The density of the hole transport layer is identical to the electron transport layer with a minus sign.”
Line 407: Add “The lowest energy peak corresponds to the energy difference between excited states, which corresponds to the second order contribution.”
Line 423: add “(orange lines)” and “(with a large period of oscillation)”
Line 529: add ”by an order of magnitude”
Line 530: add a sentence “In general, … “
Line 540: add a sentence “However, as the linear response stays oscillating around zero,...”
Line 542: add a paragraph “To assess the role of Coulomb repulsion …”
Figure 8: add figures in the lower panel that describe the nearest neighbour interaction effects. Legend changed accordingly.
Line 560: add “various weak perturbations,”
Line 575: add “and nearest-neighbour”
References 50,52,53 have been added.
Everywhere: changed “spacial” to “spatial”
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