arXiv subjects

Shu Mo

Publications and source records attributed to Shu Mo.

5 recordsLinked to original sources

arXiv2026

Disentangling bulk and surface electronic structure using targeted cleave planes in RuO$_2$

Rutile RuO$_2$ has attracted significant interest due to its putative unconventional electronic and magnetic properties and its proximity to superconductivity. However, the measurement and interpretation of its electronic structure has been complicated by a strongly three-dimensional crystal structure. Here, we demonstrate how the preparation of targeted $(110)$ and $(100)$ surfaces via focused ion beam (FIB)-engineered cleaving allows the acquisition of high-quality measurements of the electronic structure using angle-resolved photoemission spectroscopy. Our results demonstrate that ARPES spectra of RuO$_2$ are, in fact, largely dominated by signatures of distinct surface electronic states. From comparison with density-functional theory, we resolve a surface termination-dependent variation of these, and disentangle them from highly-three-dimensional bulk states and surface resonances. Moreover, we find a marked role of the substantial spin-orbit coupling of the Ru 4$d$ orbitals in the surface region, where a breaking of spatial inversion symmetry leads to significant Rashba-type spin splittings of the surface bands.

cond-mat.str-el↗

arXiv2025

peaks: a Python package for analysis of angle-resolved photoemission and related spectroscopies

The electronic band structure, describing the motion and interactions of electrons in materials, dictates the electrical, optical, and thermodynamic properties of solids. Angle-resolved photoemission spectroscopy (ARPES) provides a direct experimental probe of such electronic band structures, and so is widely employed in the study of functional, quantum, and 2D materials. \texttt{peaks} (\textbf{P}ython \textbf{E}lectron spectroscopy \textbf{A}nalysis by \textbf{K}ing group @ \textbf{S}t Andrews) provides a Python package for advanced data analysis of ARPES and related spectroscopic data. It facilitates the fast visualisation and analysis of multi-dimensional datasets, allows for the complex data hierarchy typical to ARPES experiments, and supports lazy data loading and parallel processing, reflecting the ever-increasing data volumes used in ARPES. It is designed to be run in an interactive notebook environment, with extensive inline and pop-out GUI support for data visualisation.

cond-mat.mtrl-sci↗

arXiv2025

Electronic structure of monolayer-CrTe$_2$: an antiferromagnetic 2D van der Waals material

Magnetic van der Waals materials are an important building block to realize spintronic functionalities in heterostructures of two-dimensional (2D) materials. Yet, establishing their magnetic and electronic properties and the interrelationship between the magnetic ground state and electronic structure is often challenging because only a limited number of techniques can probe magnetism and electronic structure on length scales of tens to hundreds of nanometers. Chromium chalcogenides are a class of 2D magnetic materials for which a rich interplay between structure and magnetism has been predicted. Here, we combine angle-resolved photoemission and quasi-particle interference imaging to establish the electronic structure of a monolayer of CrTe$_2$ on graphite. From a comparison of model calculations with spectroscopic mapping using angle-resolved photoemission spectroscopy and scanning tunnelling microscopy we establish the magnetic ground state and the low energy electronic structure. We demonstrate that the band structure of monolayer CrTe$_2$ is captured well by density functional theory (DFT) in a DFT+U framework when a Coulomb repulsion of $U=2.5\mathrm{eV}$ is accounted for.

cond-mat.mtrl-sci↗

arXiv2025

Hedgehog-like spin texture in Sb-doped MnBi$_2$Te$_4$

We employ spin- and angle-resolved photoemission spectroscopy and circular-dichroism ARPES to systematically investigate the spin texture of Sb-doped MnBi$_2$Te$_4$. Our results display a hedgehog-like spin texture in this system which is signified by reversed-orienting out-of-plane spins at the Dirac gap. Our finding reveals the presence of time-reversal symmetry breaking, implying the possibility for realization of high-temperature quantum anomalous Hall effect.

cond-mat.mtrl-sci↗

arXiv2023

Observation of plaid-like spin splitting in a noncoplanar antiferromagnet

Spatial, momentum and energy separation of electronic spins in condensed matter systems guides the development of novel devices where spin-polarized current is generated and manipulated. Recent attention on a set of previously overlooked symmetry operations in magnetic materials leads to the emergence of a new type of spin splitting, enabling giant and momentum-dependent spin polarization of energy bands on selected antiferromagnets. Despite the ever-growing theoretical predictions, the direct spectroscopic proof of such spin splitting is still lacking. Here, we provide solid spectroscopic and computational evidence for the existence of such materials. In the noncoplanar antiferromagnet MnTe$_2$, the in-plane components of spin are found to be antisymmetric about the high-symmetry planes of the Brillouin zone, comprising a plaid-like spin texture in the antiferromagnetic (AFM) ground state. Such an unconventional spin pattern, further found to diminish at the high-temperature paramagnetic state, stems from the intrinsic AFM order instead of spin-orbit coupling (SOC). Our finding demonstrates a new type of quadratic spin texture induced by time-reversal breaking, placing AFM spintronics on a firm basis and paving the way for studying exotic quantum phenomena in related materials.

cond-mat.mtrl-sci↗