Journal of physics. Condensed matter : an Institute of Physics journal最新文献

{"title":"Layer breathing Raman mode in two-dimensional van der Waals magnet Cr₂Ge₂Te₆.","authors":"Nilesh Choudhury, Sandeep Soni, Neesha Yadav, Mayank Shukla, Pintu Das","doi":"10.1088/1361-648X/aea95a","DOIUrl":"10.1088/1361-648X/aea95a","url":null,"abstract":"<p><p>We report the observation of a weak broad mode with characteristic dependence on thickness of flakes suggesting this as a layer breathing (LB) mode in(CGT) measured using Raman spectroscopy. Symmetry analysis confirms that the CGT falls under the non-polar category of layered material. The evolution of the LB mode frequency with increasing layer number () reveals a distinct softening trend, characteristic of weakening restoring forces in thicker flakes. By fitting the experimental Raman data using the linear chain model (LCM), we quantitatively extract the interlayer force constant (), providing a measure of the vdW coupling strength between layers. The good agreement between experimental and theoretical results establishes the LCM as a reliable framework for describing interlayer phonon dynamics in CGT. In conclusion, these findings not only deepen our understanding of interlayer interactions and symmetry-driven phonon behavior but also offer a powerful diagnostic for assuming layer thickness and structural integrity in vdW magnets. Such insights are pivotal for 2D spintronics and multifunctional device architectures based on CGT.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":"38 39","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149070823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correlation between Sm³⁺optical absorption and disorder build-up in swift heavy ion-irradiated CeO₂nanoparticles.","authors":"Jean-Marc Costantini, Gérald Lelong, Maxime Guillaumet, Gianguido Baldinozzi, Abdelali Zaki, Maik Lang","doi":"10.1088/1361-648X/aea66f","DOIUrl":"https://doi.org/10.1088/1361-648X/aea66f","url":null,"abstract":"<p><p>Diffuse reflectance spectroscopy was used to study undoped and Sm-doped CeO₂nanoparticles prepared by sol-gel and ball-milling routes, and to probe radiation damage induced by swift heavy ions. Kubelka-Munk analysis of UV-vis-NIR spectra reveals nine Sm³⁺4f-4f absorption bands within the wide O 2p-Ce 4f band gap, with intensities that increase with Sm content and remain broad owing to low local symmetry and native disorder. Under 946 MeV Au irradiation up to 5 × 10¹²cm^-2, ball-milled Sm-doped samples exhibit a systematic fluence-dependent decrease of Sm³⁺band intensities, without significant changes in bandwidth or peak positions, indicating that irradiation primarily weakens the local crystal field rather than altering site multiplicity. In parallel, the Urbach energy of the absorption edge increases, providing an optical measure of disorder build-up and yielding approximate damage cross sections consistent with electronically driven track formation. A weak Ce³⁺4f-5 d band near 15 000 cm^-1appears in irradiated undoped CeO₂but is absent in Sm-doped samples, in agreement with oxygen-potential pinning by charge-compensating vacancies. Overall, the data indicate that Sm³⁺absorption bands are sensitive optical probes of irradiation-induced disorder in nanocrystalline ceria and highlight the utility of rare-earth dopants for tracking radiation damage in fluorite-type oxide nanoparticles.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":"38 39","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149070858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topological invisibility in altermagnetic skyrmion magnonics.","authors":"Gyanti Prakash Moharana","doi":"10.1088/1361-648X/aea8b3","DOIUrl":"10.1088/1361-648X/aea8b3","url":null,"abstract":"<p><p>In this work, we demonstrate a geometric selection rule for magnons in compensated altermagnetic skyrmions. In the leading circular- and exchange-domain-odd channel, the response probes the symmetric-traceless pullback metric of the Néel texture rather than skyrmion density. Calibrating the covariant derivative transfer isolates the local source, whereis the altermagnetic exchange quadrupole. A Belavin-Polyakov skyrmion is thus a conformal null: it carries finite winding and emergent flux whilevanishes pointwise. Smooth fixed-topology deformations break conformality and restore the response linearly, separating topology from geometric shear. Starting from a two-sublattice exchange model, we derive the gauge-covariant circular-magnon operator and establish the controlled long-wavelength/WKB hierarchy. Split-step propagation benchmarks the Born-eikonal reduction, while a lattice audit tests the continuum limit. The angular node and exchange/polarization sign reversals provide differential tests of real-space magnon quantum geometry.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148983868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Resolving the true ground-state structure and origin of high-symmetry instability in lead-free perovskite RbSrI3.","authors":"Rinku Majumder, Chandrika Mondol, Arpon Chakraborty, Md Rakib Hossain, Ayon Chakrobortty, Md Salahuddin Mina, Anujoy Biswas, S M Jayed Hakim","doi":"10.1088/1361-648X/aea1ce","DOIUrl":"10.1088/1361-648X/aea1ce","url":null,"abstract":"<p><p>Inorganic halide perovskite RbSrIhas recently attracted attention as a lead-free material for radiation detection and optoelectronic applications. However, most theoretical studies have assumed an ideal cubic structure as the ground-state phase, despite the strong tendency of halide perovskites toward polymorphism and experimental evidence for an orthorhombic structure. Here, we resolve this discrepancy through a comprehensive first-principles density functional theory investigation using the GGA-PBE functional and the projector augmented-wave method as implemented in. The HSE06 hybrid functional was additionally employed to validate the calculated electronic band gaps. Energetic, dynamical, and finite-temperature thermodynamic analyses consistently identify the distorted orthorhombicphase as the true ground state, while the cubic phase is dynamically unstable. Importantly, we show that energetic ordering alone is insufficient to establish the proper ground state, since lattice-dynamical stability is essential for distinguishing a true minimum from an unstable or saddle-point structure. The instability of the high-symmetry phase is traced to an A-site-driven lattice mismatch, in which the undersized Rbcation gives rise to soft Rb-I vibrational modes that drive cooperative octahedral rotations. Crystal orbital Hamilton population analysis further shows that octahedral tilting strengthens Rb-I interactions while reducing antibonding Sr-I contributions, thereby stabilizing the distorted structure. Octahedral tilting also modifies the optoelectronic response, increasing the GGA-PBE band gap from 3.32 eV in cubicto 3.76 eV in orthorhombicphase. Higher-level HSE06 calculations confirm this trend, giving corresponding band gaps of 4.34 and 4.77 eV, respectively. The structural distortion also modifies the optical spectra significantly. These results establish the correct structural reference for RbSrIand provide a microscopic framework linking geometric mismatch, lattice dynamics, chemical bonding, and optoelectronic behavior in lead-free halide perovskites.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical role of quantum and electrical double layer capacitance in 2D electrode/ionic-liquid electrolyte based supercapacitors.","authors":"Kalyani Mohanty, Amritha Prabhu, Ashwath Subrahmanya P, Subhasmita Ray, Saikat Dutta, Nirmalya Ballav, Kartick Tarafder","doi":"10.1088/1361-648X/aea50e","DOIUrl":"10.1088/1361-648X/aea50e","url":null,"abstract":"<p><p>This work examines graphene and MXene electrodes integrated with three imidazolium-based ionic liquid electrolytes for supercapacitor applications. Quantum capacitance and electric double-layer capacitance were systematically analyzed to evaluate electrode-electrolyte performance. MXenes exhibited nearly an order of magnitude higher quantum capacitance than multilayer graphene, highlighting their superior suitability. Among the electrolytes, EMIM-TCB showed limited applicability with peak capacitance confined to zero potential. In contrast, BMIM-PFand BMIM-BFdisplayed strong compatibility, particularly with MXenes, delivering enhanced capacitance across a wide potential range due to favorable structural and electrostatic interactions. Overall, the MXene-BMIM-PFcombination emerges as a promising candidate among the investigated materials for high-performance supercapacitors, while the study emphasizes the critical role of interfacial engineering in the design of next-generation energy storage systems.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Superconductivity in metal borocarbide MBC₅and M₂BC₁₁compounds.","authors":"Ziqi Wei, Qing Tian, Wei Zhang, Weiyi Xia, C Z Wang","doi":"10.1088/1361-648X/aea50f","DOIUrl":"10.1088/1361-648X/aea50f","url":null,"abstract":"<p><p>The superconductivity of MBC₅and M₂BC₁₁ternary compounds, with M being the group 1-3 metal elements, is systematically studied by first principles calculations. Superconductivity with critical temperature<i>T</i>_cbelow 10 K is predicted for MBC₅compounds when M are alkali earth or La atoms. For M₂BC₁₁compounds, superconductivity with<i>T</i>_cbelow 5 K is predicted for M=Na, K, and Rb, while higher<i>T</i>_cis predicted for M=Mg and Ca. In particular, the Mg₂BC₁₁exhibits an exceptionally high<i>T</i>_cof 43.9 K. The results obtained by our first-principles calculations enrich our knowledge in the structure and superconductivity of metal borocarbide ternary compounds and provide useful guidance for further experimental synthesis and discovery.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Frenkel line of Yukawa fluids within the self-consistent relaxation theory<sup />.","authors":"Ilnaz I Fairushin, Anatolii V Mokshin","doi":"10.1088/1361-648X/aea1b6","DOIUrl":"10.1088/1361-648X/aea1b6","url":null,"abstract":"<p><p>For a simple model fluid, the Yukawa fluid, the condition for dynamic crossover, known as the Frenkel line, is defined. The condition is related to the fact that the roton minimum in the dispersion relation of longitudinal acoustic-like excitations exists only when the collective vibrational dynamics of particles dominates in the liquid. Based on the self-consistent relaxation theory for the Yukawa fluid, thermodynamic states are determined in which the roton minimum disappears. The obtained values of the state parameters for the Frenkel line are consistent with the results of studies in which the position of this line on the phase diagram of the Yukawa fluid was determined using molecular dynamics simulations. It is shown that the Frenkel line in this system can be determined directly from the structural characteristic-the static structure factor. A physical interpretation of the roton minimum frequency for the simple liquids near the Frenkel line is proposed.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148883360","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Landau-Khalatnikov theory of anelastic relaxations in spin-crossover materials.","authors":"Maryam Nasimsobhan, Melvyn Larranaga, William Nicolazzi, Gábor Molnár, Azzedine Bousseksou","doi":"10.1088/1361-648X/aea50d","DOIUrl":"10.1088/1361-648X/aea50d","url":null,"abstract":"<p><p>Large anelastic relaxations have been found near the transition temperature in spin crossover (SCO) materials due to stress-induced changes in spin state. To investigate the mechanistic aspects of this phenomenon, we develop here a phenomenological framework, based on the Landau theory of phase transitions, incorporating coupling terms between spin state and elastic strain, which is also extended to the dynamic Landau-Khalatnikov regime. We derive an analytical solution for the mechanical response and conduct a parametric study of a cubic SCO system. Our simulations reveal bulk modulus relaxation, internal friction peaks and renormalization of elastic constants near the spin transition-qualitatively matching recent nanoindentation experiments. The work clarifies the roles of bilinear and higher-order couplings in shaping static and dynamic elastic anomalies, with relevance for mechanical actuator design.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148922560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pressure-induced stacking disorder and suppression of long-range<i>Sm-type</i>order in medium-entropy rare-earth alloys.","authors":"Raimundas Sereika, Matthew P Clay, Kallol Chakrabarty, Yogesh K Vohra","doi":"10.1088/1361-648X/aea671","DOIUrl":"https://doi.org/10.1088/1361-648X/aea671","url":null,"abstract":"<p><p>Rare-earth medium-entropy alloys provide a platform for investigating how chemical disorder modifies the well-established pressure-induced structural evolution of close-packed 4<i>f</i>lanthanides. Here, we study TbHoEr and TbHoDy using synchrotron x-ray diffraction in diamond anvil cells. Both alloys transform from the ambient hexagonal close-packed (<i>hcp</i>) structure to a double hexagonal close-packed (<i>dhcp</i>) phase, while no well-resolved bulk<i>Sm-type</i>intermediate phase is observed. For TbHoEr, compression to 70 GPa further reveals a high-pressure rhombohedral<i>hR24</i>phase. Unlike the constituent heavy lanthanides, however, both alloys bypass the intermediate<i>Sm-type</i>phase. Two-dimensional diffraction images further reveal streak-like diffuse scattering in the transition region, indicating stacking disorder and limited stacking coherence along the close-packed direction. These observations indicate that the transformation proceeds through a stacking-disordered close-packed state rather than through a well-ordered bulk<i>Sm-type</i>phase. We propose that configurational disorder, local lattice distortion, stacking-fault energetics, and transformation kinetics collectively suppress the development of long-range<i>Sm-type</i>order. The results demonstrate that medium-entropy alloying can fundamentally modify pressure-induced stacking pathways in rare-earth materials under extreme conditions.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":"38 38","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149019207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum transport through a commensurate off-diagonal Aubry-André-Harper chain with dephasing.","authors":"Arpita Koley","doi":"10.1088/1361-648X/aea280","DOIUrl":"10.1088/1361-648X/aea280","url":null,"abstract":"<p><p>We investigate quantum transport in a commensurate off-diagonal Aubry-André-Harper (AAH) chain with modulation parameter, the smallest even-denominator supercell that supports band gap reconstruction at both zero and non-zero energies. Using a tight-binding framework combined with the Landauer-Büttiker formalism, we analyse coherent electron transport through finite lattices coupled to external electrodes. The phase-dependent energy spectrum exhibits a hierarchy of bulk-gap reconstructions associated with the six-site supercell modulation, giving rise to distinct transmission windows and resonant transport channels. Finite-size classes characterised by() modify the boundary-state configuration and shift the corresponding transmission windows. In particular, lattices with odd number of sites exhibit robust zero-energy transmission channels arising from sublattice imbalance in the bipartite hopping network. To evaluate the stability of these features under realistic conditions, environmental decoherence is incorporated through Büttiker dephasing probes. While increasing dephasing progressively suppresses interference-assisted transport, the underlying finite-size transport classification remains clearly identifiable over a broad parameter range. Our results establish clear transport signatures of commensurate off-diagonal modulation beyond the dimer limit and highlight the crucial role of supercell termination and decoherence in determining electron transport through finite AAH chains.</p>","PeriodicalId":520686,"journal":{"name":"Journal of physics. Condensed matter : an Institute of Physics journal","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148890011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}