Pseudogap-driven sign reversal of the Hall effect

Area of Science:

• Condensed matter physics
• Materials science
• Solid-state physics

Background:

• The Hall coefficient is a key property for understanding electronic behavior in materials.
• Charge density wave (CDW) states significantly alter material properties, including electronic structure and transport coefficients.
• Previous models often struggled to accurately predict Hall coefficient behavior in CDW states.

Purpose of the Study:

• To calculate the Hall coefficient in 2H-TaSe(2) and 2H-Cu(0.2)NbS(2) by integrating electronic structure data.
• To investigate the impact of the charge density wave (CDW) state on the Hall coefficient.
• To validate a theoretical approach against experimental observations without adjustable parameters.

Main Methods:

• Extraction of electronic structure from angle-resolved photoemission spectroscopy (ARPES) data.
• Application of the semiclassical Boltzmann equation for Hall coefficient calculation.
• Incorporation of spectral weight redistribution and pseudogap opening due to CDW formation.

Main Results:

• The semiclassical approach accurately predicts the normal-state Hall coefficient.
• The formation of the charge density wave state leads to pseudogap opening and spectral weight redistribution.
• The model successfully reproduces the temperature dependence of the Hall coefficient, including its sign change, in the CDW state.

Conclusions:

• The electronic structure, particularly changes associated with the charge density wave state, is crucial for understanding the Hall coefficient.
• A detailed accounting of spectral weight redistribution is essential for accurate Hall coefficient predictions in materials exhibiting CDW transitions.
• This work provides a parameter-free method for calculating the Hall coefficient in complex electronic systems.