Dimensional Crossover in a Charge Density Wave Material Probed by Angle-Resolved Photoemission Spectroscopy

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid State Physics

Background:

• Charge density waves (CDWs) are prevalent in low-dimensional materials.
• Niobium triselenide (NbSe_{3}) is a prototypical quasi-one-dimensional (quasi-1D) material exhibiting CDW properties.
• Understanding the dimensionality of electronic behavior in such materials is crucial for fundamental physics and potential applications.

Purpose of the Study:

• To investigate the dimensional crossover in NbSe_{3} from one-dimensional (1D) to three-dimensional (3D) behavior.
• To determine the energy scale governing this dimensional crossover.
• To elucidate the role of CDWs in the electronic structure and dimensionality.

Main Methods:

• High-resolution angle-resolved photoemission spectroscopy (ARPES) was employed to probe the electronic structure.
• Analysis of spectral weight depletion and Fermi surface warping.
• Detailed examination of the density of states (DOS) as a function of binding energy.

Main Results:

• Evidence of a crossover from 1D to 3D behavior was observed in NbSe_{3}.
• In the low-temperature 3D regime, electronic gaps due to two incommensurate CDWs were identified, consistent with prior x-ray diffraction and electronic-structure calculations.
• At higher temperatures, spectral weight depletion consistent with 1D power-law behavior was detected.
• The energy scale of the dimensional crossover was extracted from the warping of the quasi-1D Fermi surface.
• A binding energy-dependent change in dimensional behavior was revealed through DOS analysis.

Conclusions:

• NbSe_{3} exhibits a temperature-dependent dimensional crossover, transitioning from 1D to 3D behavior.
• The study provides a quantitative measure of the energy scale for this crossover.
• These findings offer significant insights into the nature of electronic excitations and dimensionality in quasi-1D materials.