Dimensional and doping stability of Peierls charge density waves

Aitor Garcia-Ruiz^1*, Che-pin (許哲彬)¹, Ming-Hao Liu (劉明豪)¹, Marcin Mucha-Kruczynski²

¹Physics, National Cheng Kung University, Tainan, Taiwan
²Physics, University of Bath, Bath, UK

* Presenter:Aitor Garcia-Ruiz, email:aitor_garcia-ruiz@hotmail.es

The growing interest in nanotechnology has brought renewed attention to low-dimensional materials, such as quasi-one-dimensional conductors and metallic nanowires. On the one hand, one- and two-dimensional systems represent the ultimate atomic limit in device miniaturization. On the other hand, their reduced dimensionality can be exploited to design new functionalities, as enhanced electronic correlations and many-body effects often lead to novel electronic instabilities. Among these, charge density waves (CDWs)—states in which the electronic density forms a periodic modulation accompanied by a lattice distortion—represent one of the hallmark phenomena of one-dimensional systems.

In this work, we investigate how inter-chain coupling and carrier doping affect the stability of Peierls-type CDWs in finite arrays of coupled chains. We focus on half-filled chains coupled to the q=±2π/a phonons and analyze two stacking configurations: parallel and skewed. For the former, we find that inter-chain coupling tends to suppress the CDW order. However, if the single-chain CDW gap is sufficient to overcome the energy splitting induced by the coupling, a CDW phase develops. Moreover, for an odd number of chains the presence of inter-chain coupling leads to bistability, with a new CDW phase with smaller lattice distortion and electronic band gap corresponding to a local minimum of the total energy.

Our results demonstrate how geometric stacking and electronic doping jointly tune the competition between electronic dispersion and lattice instability, offering new insights into the design of low-dimensional materials with controllable correlated phases.

Keywords: Charge Density waves, One-dimensional atomic chains, SSH model, Peierls instability