Purely anharmonic charge-density wave in the 2D Dirac semimetal SnP
arXiv:2309.05847 · doi:10.1103/PhysRevB.109.174112
Abstract
Charge density waves (CDWs) in two-dimensional (2D) materials have been a major focus of research in condensed matter physics for several decades due to their potential for quantum-based technologies. In particular, CDWs can induce a metal-insulator transition by coupling two Dirac fermions, resulting in the emergence of a topological phase. Following this idea, here we explore the behavior of three different CDWs in a new 2D layered material, SnP, using both density functional theory calculations and experimental synthesis to study its stability. The layered structure of its bulk counterpart, Sn4P3, suggests that the structure can be synthesized down to the monolayer by exfoliation or chemical means. However, despite the stability of the bulk, the monolayer shows unstable phonons at Γ, K, and M points of the Brillouin zone, which lead to three possible charge-density-wave phases. All three CDWs lead to metastable insulating phases, with the one driven by the the active phonon in the K point being topologically non-trivial under strain. Strikingly, the ground-state structure is only revealed due to the presence of strong anharmonic effects. This, underscores the importance of studying CDWs beyond the conventional harmonic picture, where the system's ground state can be elucidated solely from the harmonic phonon spectra.
References in corpus (22)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- Advanced capabilities for materials modelling with Quantum ESPRESSO
- Two-dimensional materials from high-throughput computational exfoliation of experimentally known compounds
- Intrinsic ripples in graphene
- Topological quantum chemistry
- The (High Quality) Topological Materials In The World
- Anharmonic free energies and phonon dispersions from the stochastic self-consistent harmonic approximation: application to platinum and palladium hydrides
- Extended Phonon Collapse and the Origin of the Charge-Density-Wave in NbSe
- Chiral anomaly, Charge Density Waves, and Axion Strings from Weyl Semimetals
- Evidence for an axionic charge density wave in the Weyl semimetal (TaSe4)2I
- The Stochastic Self-Consistent Harmonic Approximation: Calculating Vibrational Properties of Materials with Full Quantum and Anharmonic Effects
- All Topological Bands of All Nonmagnetic Stoichiometric Materials
- Second order structural phase transitions, free energy curvature, and temperature-dependent anharmonic phonons in the self-consistent harmonic approximation: theory and stochastic implementation
- Electron-Phonon Coupling and the Soft Phonon Mode in TiSe
- Pressure and stress tensor of complex anharmonic crystals within the stochastic self-consistent harmonic approximation
- Quantum enhancement of charge density wave in NbS in the 2D limit
- Weak Dimensionality Dependence and Dominant Role of Ionic Fluctuations in the Charge-Density-Wave Transition of NbSe
- Band Engineering of Dirac Semimetals using Charge Density Waves
- Phonon collapse and van der Waals melting of the 3D charge density wave of VSe
- Axial Higgs Mode Detected by Quantum Pathway Interference in RTe3
- Axionic Band Topology in Inversion-Symmetric Weyl-Charge-Density Waves
- Anharmonicity reveals the tunability of the charge density wave orders in monolayer VSe