Electronic Characteristics of Quasi-2D Metallochloronitrides: Na(x)HfNCL (T_c=25 K)

TL;DR

This study uses density functional theory to analyze the electronic properties of electron-doped quasi-2D metallochloronitrides, revealing their strong two-dimensionality and predicting a behavioral change at specific doping levels.

Contribution

It provides detailed electronic structure calculations for Na(x)HfNCl and related compounds, highlighting their 2D nature and doping-dependent behavior.

Findings

Electronic structure is highly two-dimensional.

Superconductivity up to 25K is observed.

Behavior changes at doping level x=0.3.

Abstract

Local density functional results are presented for the electron-doped metallochloronitrides A(x)ZrNCl and A(x)HfNCl, A = Li or Na, which superconduct up to 25K. The alkali non-stoichiometry is treated in a virtual crystal approximation. The electronic structure is strongly two dimensional, especially in the conduction band region occupied by the carriers, because the states are formed from the in-plane orbitals d_xy, d_{x^2-y^2} of the metal ion and the p_x, p_y orbitals of the N ion. We predict a change of behavior at a doping level of x=0.3.