Intrinsic defects as a source of $\textit{n}$-type conductivity in CrSBr

TL;DR

This study combines ARPES and first-principles calculations to identify intrinsic defects responsible for unintentional n-type doping in CrSBr, revealing potential pathways for electronic property control in 2D magnetic semiconductors.

Contribution

It provides a detailed defect analysis in CrSBr, identifying specific intrinsic defects as shallow donors, which was previously not well understood.

Findings

CrSBr exhibits conduction band filling indicating unintentional doping.

Cr interstitials are identified as the most favorable shallow donors.

Other donors include bromine antisites and vacancies with deeper ionization energies.

Abstract

Understanding and controlling native defects is essential for unlocking the full potential of two-dimensional magnetic semiconductors. Here, angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations are used to explore the electronic properties of bulk CrSBr. ARPES measurements reveal clear signatures of conduction band filling in as-grown crystals, indicative of unintentional doping. An analysis of intrinsic defects based on density functional theory (DFT) identifies chromium interstitials ($Cr_i$) stabilized between CrSBr layers as the most favorable shallow donors. Bromine-on-sulfur antisites ($Br_S$) and bromine vacancies ($V_{Br}$) are also found to act as potential donors, albeit with deeper ionization energies. Our results shed light on the origin of unintentional $\textit{n}$-type doping of CrSBr and pave the way for new strategies for defect control and electronic property tuning in this van der Waals magnet.