Materials Today Quantum最新文献

{"title":"Quantum metric nonlinear spin-orbit torque enhanced by topological bands","authors":"Xukun Feng ,&nbsp;Weikang Wu ,&nbsp;Hui Wang ,&nbsp;Weibo Gao ,&nbsp;Lay Kee Ang ,&nbsp;Y.X. Zhao ,&nbsp;Cong Xiao ,&nbsp;Shengyuan A. Yang","doi":"10.1016/j.mtquan.2025.100040","DOIUrl":"10.1016/j.mtquan.2025.100040","url":null,"abstract":"<div><div>Effects manifesting quantum geometry have been a focus of physics research. Here, we reveal that quantum metric plays a crucial role in nonlinear electric spin response, leading to a quantum metric spin–orbit torque. We argue that enhanced quantum metric can occur at band (anti)crossings, so the nonlinear torque could be amplified in topological metals with nodal features close to Fermi level. By applying our theory to magnetic Kane–Mele model and monolayer CrSBr, which feature nodal lines and Weyl points, we demonstrate that the quantum metric torque dominates the response, and its magnitude is significantly enhanced by topological band structures, which even surpasses the previously reported linear torques and is sufficient to drive magnetic switching by itself.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100040"},"PeriodicalIF":0.0,"publicationDate":"2025-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922718","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":"Spin interactions in decorated graphene nanoflakes with two localized spin-1/2 entities","authors":"Toshikaze Kariyado","doi":"10.1016/j.mtquan.2025.100041","DOIUrl":"10.1016/j.mtquan.2025.100041","url":null,"abstract":"<div><div>Magnetic properties of graphene nanoflakes with designed edge shapes are theoretically analyzed by means of the first-principles calculation. As a starting point, we take a nanoflake with decorated zigzag edges where no magnetism is expected. Then, it is shown that removal of one decoration unit induces a well-defined localized spin-1/2 state. When two decoration units are removed, there arise two localized spin-1/2 states. Notably, when two spins are aligned in the same edge, the spin–spin interaction is ferromagnetic, while when two spins are aligned in the opposite edges, the spin–spin interaction is antiferromagnetic. This suggests that decorated nanoflakes form a promising playground for nanoscale spin devices with tunable spin–spin interactions by designing edge shapes.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100041"},"PeriodicalIF":0.0,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143936576","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":"Innovative direct manufacturing of tungsten carbide superconducting nanowires for photon detection applications via pulsed focused ion beam induced deposition","authors":"Cristina García-Pérez ,&nbsp;Fernando J. Urbanos ,&nbsp;Gabriel Caballero ,&nbsp;Manuel R. Osorio ,&nbsp;Alicia Gómez ,&nbsp;Ramón Bernardo-Gavito ,&nbsp;Daniel Granados","doi":"10.1016/j.mtquan.2025.100043","DOIUrl":"10.1016/j.mtquan.2025.100043","url":null,"abstract":"<div><div>We present the development and optical characterization of tungsten carbide superconducting nanowire devices for photon detection. They are nanofabricated by direct deposition via pulsed focused ion beam induced deposition (PFIBID) using Tungsten Hexacarbonyl (W(CO)₆) as precursor. The nanowires exhibit a critical temperature of 4.71 K and demonstrate a notable response to low-intensity CW or pulsed laser illumination. For the first time, in-operando photoresponse low-temperature maps reveal hotspot distributions under low power illumination and localized superconductivity suppression upon high fluence photon absorption at higher powers. Dynamic response measurements under 1 MHz repetition rate, 640 nm pulsed laser excitation highlight the fast temporal response of the detectors and high operation stability near saturation. While currently operating in the multi-photon regime (9 photons/output-pulse), the findings emphasize their potential for single-photon detection with further optimization of material thickness (target &lt;25 nm) and excitation schemes. This work demonstrates the significant promise to direct nanofabricate superconducting devices based on WC for advanced quantum applications.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100043"},"PeriodicalIF":0.0,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143906267","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":"Polariton-induced unconventional superconductivity and emergent SU(2) symmetry in moiré flat bands","authors":"Kai Sun,&nbsp;Hui Deng","doi":"10.1016/j.mtquan.2025.100039","DOIUrl":"10.1016/j.mtquan.2025.100039","url":null,"abstract":"<div><div>We propose a polariton-moiré coupled system to realize an exact solvable model of strongly correlated superconductors. The polariton condensate induces intervalley attraction between moiré electrons in quasi-flat topological bands, leading to emergent SU(2) symmetry and exactly solutions of the many-body ground state. This system expands the condensate-induced superconductivity to the strong-correlation regime, enabling superconductivity at elevated temperatures and allowing the study of non-Fermi liquid states with a solvable, predictive model. It is promising as a versatile platform for emulating unconventional superconductivity and other strongly correlated phenomena in complex, correlated materials.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100039"},"PeriodicalIF":0.0,"publicationDate":"2025-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143894872","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":"Magnetic order through Kondo coupling to quantum spin liquids","authors":"M.A. Keskiner ,&nbsp;M.Ö. Oktel ,&nbsp;Natalia B. Perkins ,&nbsp;Onur Erten","doi":"10.1016/j.mtquan.2025.100038","DOIUrl":"10.1016/j.mtquan.2025.100038","url":null,"abstract":"<div><div>We study the emergence of magnetic order in localized spins that interact solely through their coupling to a Kitaev-type spin liquid. Using three toy models – the Kitaev model, the Yao–Lee model, and a square-lattice generalization of the Kitaev model – we calculate the effective exchange Hamiltonians mediated by the fractionalized excitations of these spin liquids. This setup is analogous to a Kondo lattice model, where conduction electrons are replaced by itinerant Majorana fermions. In the Kitaev model, our results show that the lowest-order perturbation theory generates short-range interactions with modified couplings and extending to sixth order introduces longer-range interactions while preserving the quantum spin-liquid ground state. Models involving more Majorana flavors on honeycomb and square lattices exhibit more complex behavior. The honeycomb Yao–Lee model with three flavors of itinerant Majorana fermions generates long-range RKKY-type interactions, leading to antiferromagnetic order and partial gapping of the Majorana fermion spectrum. In contrast, the square-lattice model produces a combination of anisotropic short- and long-range interactions, which can give rise to either a dimerized quantum paramagnetic state or an Ising antiferromagnet, depending on the parameters. These results illustrate the rich variety of magnetic orders that can be mediated by Kitaev-type spin liquids.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100038"},"PeriodicalIF":0.0,"publicationDate":"2025-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869662","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":"Structural, optical, and electronic properties of MgxZn1-xO (0 ≤ x ≤ 0.38) films pseudomorphically grown on Zn-polar ZnO substrates","authors":"Yusuke Kozuka ,&nbsp;Shunsuke Tsuda ,&nbsp;Thang Dinh Phan ,&nbsp;Koichiro Yaji ,&nbsp;Jun Uzuhashi ,&nbsp;Tadakatsu Ohkubo ,&nbsp;Takanobu Hiroto ,&nbsp;Takayuki Makino ,&nbsp;Joseph Falson ,&nbsp;Atsushi Tsukazaki ,&nbsp;Masashi Kawasaki","doi":"10.1016/j.mtquan.2025.100036","DOIUrl":"10.1016/j.mtquan.2025.100036","url":null,"abstract":"<div><div>ZnO is a typical oxide semiconductor with a wide direct band gap of 3.37 eV and offers a variety of possibilities for optical and electronic applications. Alloying with Mg into the Zn site increases the band gap, enabling band engineering. In this study, we have performed comprehensive characterizations of Mg_<em>x</em>Zn_1-<em>x</em>O thin films grown on Zn-polar ZnO substrates, which are of particular importance because of the excellent quality compared with those grown on other substrates such as Al₂O₃. We have obtained Mg content dependence of optical constants, two-dimensional carrier density, and valence band and core-level energies. These results indicate that, while the optical property is determined solely by the Mg content in the bulk, local structure, and Mg distribution can have a significant influence on the interface and surface properties.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100036"},"PeriodicalIF":0.0,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143807281","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":"First-principles prediction of anisotropic superconductivity in the nodal-line semi-metal TlTaSe2","authors":"Mukhtar Lawan Adam ,&nbsp;Ibrahim Buba Garba ,&nbsp;Sulaiman Muhammad Gana ,&nbsp;Bala Ismail Adamu ,&nbsp;Abba Alhaji Bala ,&nbsp;Abdulsalam Aji Suleiman ,&nbsp;Ahmad Hamisu ,&nbsp;Tijjani Hassan Darma ,&nbsp;Auwal Musa ,&nbsp;Abdulkadir S. Gidado","doi":"10.1016/j.mtquan.2025.100037","DOIUrl":"10.1016/j.mtquan.2025.100037","url":null,"abstract":"<div><div>Recent advances in topological quantum materials have spurred significant interest in exploring superconductors that also host nontrivial band topology, as these materials can serve as platforms for novel electronic phases and quantum technologies. TlTaSe₂ is one such non-centrosymmetric, quasi-two-dimensional semimetal with nodal-line topological features protected by mirror-reflection symmetry. In this study, we theoretically predict its superconducting properties using first-principles anisotropic Migdal–Eliashberg theory. Our results indicate that the states at the Fermi, are primarily Ta 5d and Tl 6p orbitals. Thus, exhibiting a multiband electronic structure. Notably, from our calculations, we find two distinct superconducting gaps of 2.15 meV and 4.5 meV on different Fermi surface sheets, arising from strongly anisotropic electron-phonon interactions predominantly involving in-plane vibrations of the Ta and Tl atoms. Using the Allen–Dynes-modified McMillan formula with a Coulomb pseudopotential μ* = 0.16, we predict a superconducting transition temperature Tc of 6.67 K. These findings underscore the significance of TlTaSe₂ as a candidate for topological superconductivity and provide insights into how the interplay between anisotropy, electron-phonon coupling, and nontrivial band topology can be explored for quantum computing and spintronics applications.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100037"},"PeriodicalIF":0.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Quantum computing for molecular vibrational energies: A comprehensive study","authors":"Somasundaram R. ,&nbsp;Jayaharish R. ,&nbsp;Rohith Ramanan ,&nbsp;Chandra Chowdhury","doi":"10.1016/j.mtquan.2025.100031","DOIUrl":"10.1016/j.mtquan.2025.100031","url":null,"abstract":"<div><div>In this work, we present a comprehensive comparative study between two different <em>Ansatz</em> quantum circuits, specifically the Unitary Vibrational Coupled Cluster (UVCC) and the Compact Heuristic Circuit (CHC) with use in computational chemistry. By incorporating these circuits into the Variational Quantum Eigensolver (VQE), we aim to find the vibrational ground state energy of small molecules. Our results, obtained using both the UVCC and CHC ansatzes with and without quantum hardware noise, are benchmarked against classical computational methods for energy state determination. We emphasize the efficiency and accuracy of the CHC <em>Ansatz</em>, which significantly reduces circuit complexity without sacrificing the fidelity of the results. This characteristic demonstrates the potential of the CHC <em>Ansatz</em> for scalable quantum chemistry applications, particularly in the Noisy Intermediate-Scale Quantum (NISQ) era. Furthermore, we employ the CHC <em>Ansatz</em> in conjunction with the Variational Quantum Deflation (VQD) algorithm to determine the excited vibrational state energies, which is compared against the reliable method of quantum Equation of Motion(qEOM). Through this comparative study, we aim to provide valuable insights into the practical applications of these <em>Ansatz</em> in quantum simulations of molecular systems, highlighting their respective advantages and potential for future quantum chemistry research.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100031"},"PeriodicalIF":0.0,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817226","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":"Ultrafast dynamics and tunable coherent optical phonons via hybridization and gold layering in hybrid topological Bi2Se1.5Te1.5","authors":"Prince Sharma ,&nbsp;Rahul Sharma ,&nbsp;Saurabh Saini ,&nbsp;Kapil Kumar ,&nbsp;Sumeet Walia ,&nbsp;Mahesh Kumar","doi":"10.1016/j.mtquan.2025.100035","DOIUrl":"10.1016/j.mtquan.2025.100035","url":null,"abstract":"<div><div>Topological insulators (TIs) are quantum materials that offer exotic optoelectronic, magnetic, and spintronic properties and lead to numerous applications such as quantum computing, Majorana Fermions, superconductivity, terahertz frequency generation, spintronics, thermoelectricity, and optoelectronics. TIs are inherently insulating in bulk, but, the topologically active surface states offer free electrons on the surfaces to enable them to be conducted on the surface. However, binary tetradymites (Bi₂Se₃, Bi₂Te₃, and Sb₂Te₃) are not fully insulating in bulk due to their semiconducting characteristics. To overcome this behaviour, the pure TIs can be converted to a new class of hybrid topological insulators (HTI) via doping. In this article, we present a detailed analysis of such kinds of HTI Bi₂Se_1.5Te_1.5 by examining their symmetry, band structure, charge carrier and phonon dynamics. Unlike pure TIs, this HTI possesses distinct optical properties, which are explored in this study. Additionally, a 15 nm gold film is deposited on TIs (Bi₂Se₃ and Bi₂Te₃) and HTI (Bi₂Se_1.5Te_1.5) crystal flakes to investigate the interaction between gold (Au) plasmonic coupling with these materials using transient reflectance spectroscopy. The main goal of Au is to tune the optical response of TIs through the plasmonic effect of Au. Besides carrier dynamics, the study also examines coherent acoustic and optical phonons in Bi₂Se₃, Bi₂Te₃ and Bi₂Se_1.5Te_1.5 as well as along with Au layered micro flakes. The hybrid Bi₂Se_1.5Te_1.5 topological material and gold layering introduce new opportunities for optoelectronics and spintronics, offering broad tunability in various optical and near-infrared regions.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100035"},"PeriodicalIF":0.0,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strongly confined Te quantum dots as building blocks for single photon sources","authors":"Rajendra Subedi ,&nbsp;Francisco Ruiz-Zepeda ,&nbsp;Yagya Bahadur Woli ,&nbsp;Thang Ba Hoang ,&nbsp;Julien Chaste ,&nbsp;Etienne Herth ,&nbsp;Grégory Guisbiers","doi":"10.1016/j.mtquan.2025.100034","DOIUrl":"10.1016/j.mtquan.2025.100034","url":null,"abstract":"<div><div>Tellurium is a heavy chemical element exhibiting chirality, anisotropy, and strong spin-orbit coupling; consequently, displaying a huge potential in quantum hardware technologies. In this article, tellurium quantum dots, with sizes around 19 ± 3 nm and energy bandgap around 2.4 eV, were successfully synthesized by pulsed laser ablation in liquids (PLAL). The synthesis was performed by using a nanosecond Nd:YAG laser emitting at 1064 nm and pulsing the laser beam at 1 kHz. Toluene (C₆H₅CH₃) was used as a solvent to avoid oxidation of the dots. Non-polarized and polarized Raman spectroscopy as well as X-Ray diffraction were performed on the dots to study their quantum confinement and anisotropy. Finally, strongly confined tellurium quantum dots were obtained; and, their properties underline their potential as quantum light sources.</div></div>","PeriodicalId":100894,"journal":{"name":"Materials Today Quantum","volume":"6 ","pages":"Article 100034"},"PeriodicalIF":0.0,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}