arXiv subjects

Damian Brzozowski

Publications and source records attributed to Damian Brzozowski.

4 recordsLinked to original sources

arXiv2026

Tailoring Emergent Magnetic Moment in La$_{0.7}$Sr$_{0.3}$MnO$_3$-Bi$_2$Te$_3$ Heterostructures via Interfacial Reconstructions

We report emergent magnetic behavior in heterostructures composed of (111)-oriented La$_{0.7}$Sr$_{0.3}$MnO$_3$ (LSMO) and (00$l$)-oriented Bi$_2$Te$_3$ (BT), controlled by interfacial reconstructions. When BT is deposited directly onto LSMO, an intermediate interfacial layer forms between the two materials. Polarized Neutron Reflectometry modeling reveals that this reconstructed region stabilizes a secondary magnetically ordered phase that is coupled to the underlying ferromagnetic LSMO layer. As a consequence, the heterostructures exhibit unconventional self-crossing magnetic hysteresis loops at room temperature, characterized by a reversal of the net magnetization at low applied fields. In contrast, the introduction of a tellurium seed layer results in a sharper LSMO-BT interface, while preserving the anomalous hysteresis behavior and enhancing the saturation magnetization. Element-specific X-ray absorption spectroscopy suggests that the emergent magnetic phase originates from the chemical reconstruction of manganese species. These results demonstrate that interface engineering in magnetic oxide-topological insulator heterostructures provides a pathway to control emergent magnetic coupling and emergent magnetic states in oxide-topological insulator heterostructures.

cond-mat.mtrl-sci↗

arXiv2026

Substrate-controlled nucleation and growth kinetics in ultrathin Bi$_2$Te$_3$ films

Metal chalcogenides are promising layered topological materials, yet their electronic performance is often limited by parasitic bulk conduction arising from defects that introduce excess carriers and shift the Fermi level out of the topological regime. Controlling early-stage growth and defect formation is therefore essential for suppressing bulk transport and enhancing surface-state conduction. Here we investigate ultrathin Bi2Te3 films grown by pulsed laser deposition on substrates spanning van der Waals, lattice-matched, and amorphous regimes to determine how substrate-dependent nucleation pathways influence defect formation and electronic transport. Phase-pure, c-axis-oriented Bi2Te3 forms on all substrates, but the growth morphology varies strongly. Layered growth with well-defined quintuple-layer terraces is governed primarily by substrate roughness rather than lattice match: atomically smooth mica and step-terraced SrTiO3 yield continuous terraces, whereas rougher BaF2 and amorphous Si3N4 produce island-structured films. Between the two smooth substrates, the higher surface energy of SrTiO3 enhances adatom adsorption and nucleation density, promoting rapid vertical growth and early Te depletion. Transport measurements reveal n-type conduction with carrier densities of 10e19-10e20 cm-3. The highest carrier density occurs for films on SrTiO3, consistent with defect formation during high-density nucleation, whereas mobility correlates with structural coherence and terrace formation. Weak anti-localization signatures confirm phase-coherent transport in films on mica and SrTiO3. These results show that substrate roughness and nucleation density provide key levers for controlling defect formation and strengthening topological surface transport in Bi2Te3 thin films.

cond-mat.mtrl-sci↗

arXiv2026

Electronic Structure and Resonant Circular Dichroism of La$_{0.7}$Sr$_{0.3}$MnO$_3$ from Soft X-ray Angle-Resolved Photoemission

Coupling between spin, orbital, charge, and lattice degrees of freedom in transition-metal oxides produces a variety of electronic and magnetic phenomena of importance for future technologies. Here, we explore the electronic band structure of a (111)-oriented La0.7Sr0.3MnO3 thin film through soft X-ray angle-resolved photoemission spectroscopy (ARPES). The measurements agree with the electronic band structure calculated with density functional theory using Hubbard U correction. Furthermore, we probe the circular dichroism in ARPES, and observe a pronounced momentum- resolved magnetic circular dichroism in resonant photoemission from the Mn L-edge. The approach combines the momentum- and spin-selectivity of ARPES and X-ray magnetic circular dichroism, respectively, which could provide a useful approach for the study of unconventional magnetism.

cond-mat.str-el↗

arXiv2025

Growth control of highly textured Bi2Te3 thin films by pulsed laser deposition

Two-dimensional materials have attracted growing interest due to their unique electronic properties and potential applications in spintronics. Interfacing strongly spin-orbit-coupled chalcogenides with functional oxides such as perovskites has a particularly high potential. In this work, highly textured Bi2Te3 thin films were deposited on (111) oriented SrTiO3 by pulsed laser deposition. We show that, by careful selection of the temperature and pressure of growth, the film's stoichiometry can be manipulated between direct stoichiometry transfer from the target and tellurium-deficient phases. Optimized pulsed laser deposition enables the growth of films with coalesced, faceted grains with grain sizes reaching up to 430 nm, while preserving crystalline quality comparable to that of molecular-beam-epitaxy-grown films. We show striking differences arising from tuning the laser's pulsing frequency and fluence, which lead to changes in surface roughness, the film's porosity, and grain boundaries, as well as grain shape. Analysis of cross-sectional transmission electron microscopy images reveals a sharp substrate-film interface without atomic intermixing and without the formation of amorphous intermediate layers. The results demonstrate that pulsed laser deposition is a viable method for producing high-quality Bi2Te3 thin films and opens the door to the integration of chalcogenides with perovskites with this growth technique.

cond-mat.mtrl-sci↗