[Paper Review] Pressure dependent topological, superconducting, optoelectronic and thermophysical properties of Ta2Se chalcogenide: Theoretical insights

Tauhidur Rahman, Jubair Hossan Abir+5 more|arXiv (Cornell University)|Feb 10, 2026

2D Materials and Applications0 citations

TL;DR

A first-principles study of Ta2Se under hydrostatic pressure (0–10 GPa) showing persistent metallicity, dynamical stability, and weak-coupling superconductivity with Tc ~3.9 K, with pressure tuning of thermophysical and optoelectronic properties.

ABSTRACT

Tetragonal Ta2Se is a layered, Ta-rich chalcogenide that departs from conventional MX2 transition-metal dichalcogenides by hosting dense Ta-Ta networks capped by Se square-net layers. Here, we present a unified first-principles investigation of hydrostatic-pressure tuning in Ta2Se from 0 to 10 GPa, connecting the structural response, mechanical stability, thermophysical indicators, bonding evolution, electronic and optical behavior, lattice dynamics and superconductivity within a single framework. The derived thermophysical descriptors corroborate a pressure-stiffened lattice: density increases, Debye temperature rises, melting temperature is elevated and minimum thermal conductivity increases, whereas the Grüneisen parameter remains within a narrow window, suggesting no anomalous anharmonic softening. Bond population metrics and electron-density-difference analysis revealed a mixed metallic-covalent bonding picture dominated by a robust Ta-Ta metallic backbone, accompanied by pressure-strengthened Ta-Se hybridization. Electronic-structure calculations show persistent metallicity under compression; pressure broadens bands, reduces density of states at the Fermi level, reshapes the Fermi surface and points to a possible Lifshitz-type reconstruction without symmetry breaking. The optical response remained metallic with Drude-like low-energy behavior and pressure-tunable spectral features. The phonon dispersions exhibit no imaginary modes, confirming dynamical stability. Electron-phonon coupling calculations classify Ta2Se as a weak-coupling, phonon-mediated superconductor with Tc around 3.9 K, consistent with available experiments and establish pressure as a practical control knob for stability and superconductivity-relevant descriptors in this metal-rich layered platform.

Motivation & Objective

• Understand how hydrostatic pressure affects the structural response and mechanical stability of Ta2Se from 0 to 10 GPa.
• Characterize thermophysical indicators and bonding evolution under pressure.
• Investigate changes in electronic structure, Fermi surface, and optical response under compression.
• Assess lattice dynamics for dynamical stability via phonon dispersions.
• Estimate the superconducting propensity and Tc under pressure through electron-phonon coupling calculations.

Proposed method

• Perform unified first-principles calculations across 0–10 GPa to connect structural, mechanical, thermophysical, bonding, electronic, optical, lattice-dynamic, and superconducting properties.
• Compute thermophysical descriptors (density, Debye temperature, melting temperature, minimum thermal conductivity, Grüneisen parameter) under pressure.
• Analyze bond populations and electron-density-difference maps to reveal bonding evolution.
• Calculate electronic structure to examine metallicity, band broadening, DOS at E_F and possible Lifshitz-type reconstruction.
• Evaluate phonon spectra for dynamical stability and compute electron-phonon coupling to estimate Tc.

Experimental results

Research questions

• RQ1 How does hydrostatic pressure influence the structural stability and bonding in Ta2Se?
• RQ2 What are the thermophysical and bonding evolutions of Ta2Se under compression?
• RQ3 How does pressure affect the electronic structure and Fermi surface of Ta2Se?
• RQ4 Is Ta2Se dynamically stable under pressure, and what is the nature of its superconductivity under compression?

Key findings

• Ta2Se remains metallic under compression with pressure-broadened bands and a reduced DOS at the Fermi level.
• Phonon dispersions show no imaginary modes, indicating dynamical stability up to 10 GPa.
• Electron-phonon coupling places Ta2Se in the weak-coupling, phonon-mediated superconductor regime with Tc around 3.9 K.
• Pressure stiffens the lattice, increasing density, Debye temperature, melting temperature, and minimum thermal conductivity, with the Grüneisen parameter remaining in a narrow range.
• Ta2Se exhibits pressure-strengthened Ta–Se hybridization and a robust Ta–Ta metallic backbone, with possible Lifshitz-type Fermi surface reconstruction without symmetry breaking.