Abstract

(Formula presented.) (Formula presented.) is a unique magnetic material. It features bulk 3D magnetic order at low temperatures, but its quantum critical behavior in a magnetic field is well described by the 1D transverse-field Ising universality class. This behavior is facilitated by the structural arrangement of magnetic (Formula presented.) ions in nearly isolated zig-zag chains. In this work, we investigate the effect of random site dilution on the critical properties of such a quasi-1D quantum Ising system. To this end, we introduce an anisotropic site-diluted 3D transverse-field Ising model. We find that site dilution leads to unconventional activated scaling behavior at the quantum phase transition. Interestingly, the critical exponents of the quantum critical point are in good agreement with those of the disordered 3D transverse-field Ising universality class, despite the strong spatial anisotropy. We discuss the generality of our findings as well as implications for experiments.

Department(s)

Physics

Publication Status

Full Access

Keywords and Phrases

cobalt niobate; disordered magnetic systems; quantum phase transitions; transverse-field Ising model

International Standard Serial Number (ISSN)

1521-3889; 0003-3804

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 Wiley; Wiley-VCH Verlag, All rights reserved.

Publication Date

01 Jan 2026

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