arXiv subjects

Maximilian F. X. Dorfner

Publications and source records attributed to Maximilian F. X. Dorfner.

2 recordsLinked to original sources

arXiv2026

Charge Transport Framework for Crystalline pi-Conjugated Materials

Quantitative charge-transport modelling in crystalline pi-conjugated polymers requires an electronic representation that captures extended conjugation and material-specific electron-phonon interactions on equal footing. We present a Wannier-orbital-based formulation of the transient-polaron-localization (TPL) framework for quantitative charge-transport simulations in crystalline pi-conjugated polymers. By expressing all interactions directly in a Wannier representation derived from first-principles calculations, the approach avoids artificial fragmentation of polymer backbones and enables a consistent, material-specific description of electronic couplings and electron-phonon interactions. Low- and high-frequency vibrational modes are incorporated within a mode-resolved TPL formalism, yielding an effective electronic Hamiltonian that captures both dynamic disorder and polaronic renormalization. The methodology is demonstrated for the ambipolar crystalline naphthalenediimide-bithiophene copolymer, enabling a direct comparison of electron and hole transport along the polymer backbone and pi-stacking directions. The simulations reproduce key transport features, including pronounced anisotropy and higher electron than hole mobility. Additional studies on single- and bi-chain systems reveal the essential role of inter-chain coherence in supporting efficient transport along the polymer backbone. Beyond this specific system, the Wannier-orbital-based TPL framework provides a transferable route to disentangle intrinsic charge-transport mechanisms in crystalline pi-conjugated materials and establishes a foundation for future work.

cond-mat.mtrl-sci↗

arXiv2025

Evaluating First-Principles Electron-Phonon Couplings: Consistency Across Methods and Implementations

Electron-phonon coupling (EPC) is fundamental for understanding the behavior of molecules and crystals, influencing phenomena such as charge transport, energy transfer, phase transitions, and polaron formation. Accurate computational methods to calculate EPCs from first principles are essential, but their complexity has resulted in a variety of computational strategies, raising concerns about their mutual consistency. In this study, we provide a systematic benchmark of methods for EPC calculation by comparing two fundamentally different {\it ab initio} methodologies. We investigate Gaussian-type orbital methods based on the \textsc{CP2K} code and plane-wave-based projector-augmented-wave (PAW) methods combined with maximally localized Wannier functions, as implemented in \textsc{VASP} and \textsc{wannier90}. In addition, we further distinguish between the derivative--of--Hamiltonian ($dH$) and derivative--of--states ($dψ$) approaches for obtaining EPC parameters. The comparison is conducted on a representative set of organic molecules, including pyrazine, pyridine, bithiophene, and quarterthiophene, varying significantly in size and flexibility. We find excellent agreement across implementations and basis sets when employing the same computational approach ($dH$ or $dψ$), demonstrating robust consistency between the numerical schemes. However, noticeable deviations occur when comparing the $dH$ and $dψ$ approaches within each code and for specific cases discussed in detail. Our findings emphasize the reliability of EPC computations using the $dH$ method and caution against potential pitfalls associated with the $dψ$ approach, providing guidance for future EPC calculations and model parameterizations.

physics.chem-ph↗