Emergent Anisotropic Non-Fermi Liquid at a Topological Phase Transition in Three Dimensions.

Area of Science:

• Condensed Matter Physics
• Quantum Materials
• Topological Phases of Matter

Background:

• Correlation effects in topological phases are crucial for understanding quantum matter.
• Topological quantum phase transitions (TQPTs) represent a frontier in condensed matter physics.
• Double-Weyl semimetals (DWSMs) are a specific topological phase with unique electronic properties.

Purpose of the Study:

• To investigate TQPTs between DWSMs and insulators.
• To characterize the emergent quantum criticality at these transitions.
• To explore the role of Coulomb interactions and electronic critical modes.

Main Methods:

• Application of standard renormalization group (RG) methods.
• Utilizing large N_{f} theory (fermion flavor number N_{f}).
• Employing the epsilon (ε) expansion method (ε=4-d, where d is spatial dimension).

Main Results:

• Identification of a novel class of quantum criticality at the TQPT.
• Emergence of anisotropic non-Fermi-liquid behaviors.
• Anisotropic renormalization of Coulomb interaction and strongly correlated electronic excitations in 3D.
• Calculation of anomalous electron dimensions (η_{f}=0.366/N_{f}) in the large N_{f} limit.
• Derivation of anisotropic scaling relations for physical observables.

Conclusions:

• The study reveals new quantum critical phenomena at DWSM-insulator TQPTs.
• Anisotropic non-Fermi-liquid behavior is a key characteristic driven by interactions.
• Findings may be observable in candidate DWSM materials like HgCr_{2}Se_{4} and SrSi_{2} near TQPT.