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Physical review. B./Physical review. B

Hamiltonian of the S = 1 2 dimerized antiferromagnetic-ferromagnetic quantum spin chain BaCu 2 V 2 O 8

Ekaterina S. Klyushina, A. T. M. N. Islam, J. T. Park, E. A. Goremychkin, Elisa M. Wheeler, Bastian Klemke, B. Lake

Published Sep 12, 2018• 9 citations
Publisher

Abstract

The novel quantum magnet ${\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ was recently discovered to be a rare physical realization of a one-dimensional antiferromagnetic-ferromagnetic dimerized chain which displays strongly correlated phenomena at elevated temperatures [E. S. Klyushina et al., Phys. Rev. B 93, 241109(R) (2016)]. This paper presents an extended study of the Hamiltonian of ${\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ at base temperature. Static susceptibility and inelastic neutron scattering data are compared to several theoretical models. An analytical relation for the dynamic structure factor of the complex unit cell of ${\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ is derived and used to identify the intrachain exchange paths. Further analysis using the first moment of the dynamic structure factor was employed to determine the exchange path responsible for the intradimer interaction. This analysis reveals that the dimer chain is formed by a dominant antiferromagnetic exchange interaction ${J}_{\mathrm{intra}}=40.92\phantom{\rule{0.28em}{0ex}}\mathrm{meV}$ which is realized via the Cu-O-V(II)-O-Cu superexchange path and a weak ferromagnetic coupling ${J}_{\mathrm{inter}}=\ensuremath{-}11.97$ meV which arises within the copper-oxygen double plaquettes.

DOI
10.1103/physrevb.98.104413

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Magnetic excitations in the S=12 antiferromagnetic-ferromagnetic chain compound BaCu2V2O8 at zero and finite temperature

Ekaterina S. Klyushina, Alexander C. Tiegel, Benedikt Fauseweh +7 more

Unlike most quantum systems which rapidly become incoherent as temperature is raised, strong correlations persist at elevated temperatures in $S=\frac{1}{2}$ dimer magnets, as revealed by the unusual asymmetric line shape of their excitations at finite temperatures. Here, we quantitatively explore and parametrize the strongly correlated magnetic excitations at finite temperatures using high-resolution inelastic neutron scattering of the model compound ${\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}$ which we show to be an alternating antiferromagnetic-ferromagnetic $\mathrm{spin}\ensuremath{-}\frac{1}{2}$ chain. Comparison to state of the art computational techniques shows excellent agreement over a wide temperature range. Our findings hence demonstrate the possibility to quantitatively predict coherent behavior at elevated temperatures in quantum magnets.

arXiv:1602.06184•Physical review. B./Physical review. B•Jun 20, 2016•21 citations

Dynamical Studies of Antiferromagnetic Exchange Interactions in Low Dimensional Quantum Spin Systems

Various forms of antiferromagnetic exchange interaction among quantized spins in one-dimensional and quasi-one-dimensional lattices are examined. Primary results are reported in two real compounds, the sodium vanadate NaV2O5 and the copper germanate CuGeO3, and in a class of compounds of real materials modeled as dimerized antiferromagnetically coupled spin-1/2 chains susceptible to spin-1 impurity doping and that include such examples as the strontium cuprate Sr14Cu24O41 and vanadium pyrophosphate (VO)2P2O7. Sodium vanadate, NaV2O5, a quarter-filled two-leg ladder compound that was originally thought to be composed of magnetic legs and nonmagnetic legs was subsequently shown to be a charge ordered system below room temperature. Initial models of the material as isolated antiferromagnetically coupled spin-1/2 chains can be mapped to the subsequently resolved magnetic system of the charge ordered state with the spins on molecular orbitals of V-O-V rungs antiferromagentically coupled between neighboring rungs either on the same ladder or on neighboring ladders. Comparing the model's dynamic structure factor to inelastic neutron scattering data could distinguish between the proposed spin coupling schemes and consequently reveal the details of the interaction between the lattice and the "zig-zag" charge density as well as the magnetic stabilization of the low temperature phase. Copper germanate, the first and only known inorganic spin-Peierls compound, exhibits a strong temperature dependent exchange coupling pattern among the spin-1/2 Cu2+ chains. Above the spin-Peierls transition temperature an unmodulated antiferromagnetic nearest neighbor exchange interaction J1 competes with an antiferromagnetic next nearest neighbor interaction J2. The next nearest neighbor exchange represents an effective coupling equivalent to the net effect of all longer range exchange interactions. This frustration to the nearest neighbor spin exchange produces a distinctive magnetic susceptibility χ (T) much different from the Bonner-Fisher susceptibility of the spin-1/2 Heisenberg chain with nearest neighbor antiferromagnetic exchange only. The ratio of the second to first nearest neighbor couplings α = J2/J1 ≈ 0.36 is sufficient to open a spontaneous gap in the spin-wave excitation spectrum at low temperatures. Below TSP = 14K, the dynamical structure factor is used to fit the dimerization δ and the exchange interactions J1 and J2 to the inelastic neutron scattering data of CuGeO3 at T = 10K. It is found that both δ and α increase significantly at lower temperatures, relative to the values obtained in the high temperature phase and at the onset of dimeration at 14 K. Static structure factor calculations how Scattering inconsistent with the δ−J1−J2 model and can be attributed primarily to the phonon degrees of freedom but possibly also to the couplings between chains in the b and a directions of the crystal lattice. Structurally dimerized compounds of antiferromagnetic spin-1/2 chains possess dynamic structure factor and magnetic susceptibility features that are very sensitive to doping with magnetic and nonmagnetic impurities. It is shown that the effects of spin-1 impurities are very similar to those of nonmagnetic (S = 0) impurities if the coupling between impurity and native spin is about the same magnitude as or larger than between native S = 1/2 spins. The microscopic origins of the similarity can be appreciated with the consideration that neighboring spins to the impurity find it more energetically favorable to couple to the impurity than the other spins of the lattice. Thus the spin-1 impurity and its neighboring S = 1/2 spins decouple from the lattice, creating a nonmagnetic break in the chain. The spins that now observe a nonmagnetic cluster on one side can couple to the S = 1/2 spins on the other side with a higher AF correlation than in the pure compound since they do not have to have a fluctuating dimer resonating between two neighbors. Such enhancements to the local correlations can stabilize the global AF order in one dimensional compounds as shown in theoretical and experimental studies of CuGeO3. ED calculations of the dynamic structure factor show that S(q, ω) developes states with ω = 0 in the gap at q = π. Magnetic susceptibilites in the presense of spin-1 impurities were obtained for 80 site chains by QMC simulations and for 16 site chains by ED calculations. An impurity concentration-dependent second peak in the low temperature region reveals an increasing second maximum with T as observed in doped copper germanates and suggests that the results of the study are applicable even to phonon mediated dimerization. This is not immediately apparent because spin-phonon coupling could distort the dimerization patterns. However, experimental and theoretical results show that elastic coupling between chains can stabilize the dimerization pattern due to the impurities and the results will still apply.

•Jan 1, 2003•0 citations

Hybridization and spin-orbit coupling effects in the quasi-one-dimensional spin- 1 2 magnet Ba 3 Cu 3 Sc 4 O 12

Danis I. Badrtdinov, О. С. Волкова, Alexander A. Tsirlin +3 more

We study electronic and magnetic properties of the quasi-one-dimensional spin-$\frac{1}{2}$ magnet ${\mathrm{Ba}}_{3}{\mathrm{Cu}}_{3}{\mathrm{Sc}}_{4}{\mathrm{O}}_{12}$ with a distinct orthogonal connectivity of ${\mathrm{CuO}}_{4}$ plaquettes. An effective low-energy model taking into account spin-orbit coupling was constructed by means of first-principles calculations. On this basis, a complete microscopic magnetic model of ${\mathrm{Ba}}_{3}{\mathrm{Cu}}_{3}{\mathrm{Sc}}_{4}{\mathrm{O}}_{12}$, including symmetric and antisymmetric anisotropic exchange interactions, is derived. The anisotropic exchanges are obtained from a distinct first-principles numerical scheme combining, on one hand, the local density approximation taking into account spin-orbit coupling, and, on the other hand, a projection procedure along with the microscopic theory by Moriya [Phys. Rev. 120, 91 (1960)]. The resulting tensors of the symmetric anisotropy favor collinear magnetic order along the structural chains with the leading ferromagnetic coupling ${J}_{1}\ensuremath{\simeq}\ensuremath{-}9.88$ meV. The interchain interactions ${J}_{8}\ensuremath{\simeq}0.21$ and ${J}_{5}\ensuremath{\simeq}0.093$ meV are antiferromagnetic. Quantum Monte Carlo simulations demonstrate that the proposed model reproduces the experimental Neel temperature, magnetization, and magnetic susceptibility data. The modeling of neutron-diffraction data reveals an important role of the covalent Cu-O bonding in ${\mathrm{Ba}}_{3}{\mathrm{Cu}}_{3}{\mathrm{Sc}}_{4}{\mathrm{O}}_{12}$.

arXiv:1604.03333•Physical review. B./Physical review. B•Aug 31, 2016•11 citations

Static and dynamic properties of a dimerized quantum-spin chain

Oliver Fritz, Stephen William Lovesey, Greg I Watson

Various static spin-correlation functions and the weights of the spin excitations, or collective normal modes, in the van Hove response function, observed in neutron scattering experiments, are calculated as a function of temperature for a model quantum-spin chain. The spins interact through an isotropic Heisenberg exchange that extends to nearest-neighbour spins. In our model, spins of magnitude 1/2 form a dimerized chain with alternating exchange interactions. We explore the static and dynamic properties for ferromagnetic and antiferromagnetic exchange interactions. Results for the various properties are shown to be exact in the limit of a high temperature, and we argue that the results are very good at low temperatures. Unlike the case for linear spin-wave theory, the results are also exact in the limit of strong dimerization, i.e. non-interacting coupled pairs of spins.

Journal of Physics Condensed Matter•Jul 20, 1998•1 citation

Spin Dynamics of the Spin-Ladder Dimer-Chain Material Sr14Cu24O41

Roger S. Eccleston, M. Uehara, Jun Akimitsu +3 more

We have performed inelastic neutron scattering on a single crystal sample of ${\mathrm{Sr}}_{14}{\mathrm{Cu}}_{24}{\mathrm{O}}_{41}$ to study the spin dynamics of the ${\mathrm{Cu}}_{2}{\mathrm{O}}_{3}$ spin ladder layers and ${\mathrm{CuO}}_{2}$ chains. Our data are best fitted with a dispersion which has a spin gap of $32.5\ifmmode\pm\else\textpm\fi{}0.1\mathrm{meV}$ and a maximum of $193.5\ifmmode\pm\else\textpm\fi{}2.4\mathrm{meV}$, consistent with a coupling along the ladders, ${J}_{\ensuremath{\parallel}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}130\phantom{\rule{0ex}{0ex}}\mathrm{meV}$ and a rung coupling ${J}_{\ensuremath{\perp}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}72\mathrm{meV}$. Excitations with an energy transfer of approximately 11.5 meV arise from a dimer chain with an antiferromagnetic intradimer coupling ${J}_{1}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}11.2\mathrm{meV}$ between next-nearest-neighbor Cu ions, and a ferromagnetic interdimer coupling ${J}_{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}1.1\mathrm{meV}$. The dimer chains have a periodicity of five units.

arXiv:cond-mat/9711053•Physical Review Letters•Aug 24, 1998•186 citations

Interplay of alternation and further neighbor interaction in S=12 spin chains: A case study of Cs2CuAl4O8

Badiur Rahaman, Satyaki Kar, Alexander N. Vasiliev +1 more

Using Wannier function formulation and total energy calculations by first-principles density functional theory (DFT), we derive the underlying spin model of a recently synthesized compound, ${\mathrm{Cs}}_{2}{\mathrm{CuAl}}_{4}{\mathrm{O}}_{8}$, having zeolitelike network structure. The computed magnetic interactions show that the interchain Cu-Cu interactions are negligibly small compared to intrachain Cu-Cu interactions, thus characterizing ${\mathrm{Cs}}_{2}{\mathrm{CuAl}}_{4}{\mathrm{O}}_{8}$ as a prototypical one-dimensional (1D) spin-$\frac{1}{2}$ system. Interestingly, the DFT-derived 1D spin model features a combination of alternating ferromagnetic-antiferromagnetic interactions, together with the presence of both nearest- and next-nearest-neighbor interactions, making it an unprecedented case. The solution of the derived spin model of the compound using the quantum Monte Carlo technique shows reasonably good agreement with the experimental susceptibility data, measured in the presence of the magnetic field. The presence of spin gap is suggested by quantum Monte Carlo simulations in the zero-field condition, which is cross-checked by a more rigorous exact diagonalization study. Motivated by the intricacy of the derived spin model, we further examine the ground-state properties of this model in the parameter space of exchange interactions, which shows the possibility of driving quantum phase transition between gapped and gapless spin excitation. Our study is expected to shed light on the fascinating world of 1D quantum spin systems.

Physical review. B./Physical review. B•Oct 8, 2018•9 citations
The novel quantum magnet BaCu2V2O8{\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}BaCu2​V2​O8​ was recently discovered to be a rare physical realization of a one-dimensional antiferromagnetic-ferromagnetic dimerized chain which displays strongly correlated phenomena at elevated temperatures [E. S. Klyushina et al., Phys. Rev. B 93, 241109(R) (2016)]. This paper presents an extended study of the Hamiltonian of BaCu2V2O8{\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}BaCu2​V2​O8​ at base temperature. Static susceptibility and inelastic neutron scattering data are compared to several theoretical models. An analytical relation for the dynamic structure factor of the complex unit cell of BaCu2V2O8{\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}BaCu2​V2​O8​ is derived and used to identify the intrachain exchange paths. Further analysis using the first moment of the dynamic structure factor was employed to determine the exchange path responsible for the intradimer interaction. This analysis reveals that the dimer chain is formed by a dominant antiferromagnetic exchange interaction Jintra=40.92meV{J}_{\mathrm{intra}}=40.92\phantom{\rule{0.28em}{0ex}}\mathrm{meV}Jintra​=40.92meV which is realized via the Cu-O-V(II)-O-Cu superexchange path and a weak ferromagnetic coupling Jinter=\ensuremath−11.97{J}_{\mathrm{inter}}=\ensuremath{-}11.97Jinter​=\ensuremath−11.97 meV which arises within the copper-oxygen double plaquettes.
Unlike most quantum systems which rapidly become incoherent as temperature is raised, strong correlations persist at elevated temperatures in S=12S=\frac{1}{2}S=21​ dimer magnets, as revealed by the unusual asymmetric line shape of their excitations at finite temperatures. Here, we quantitatively explore and parametrize the strongly correlated magnetic excitations at finite temperatures using high-resolution inelastic neutron scattering of the model compound BaCu2V2O8{\mathrm{BaCu}}_{2}{\mathrm{V}}_{2}{\mathrm{O}}_{8}BaCu2​V2​O8​ which we show to be an alternating antiferromagnetic-ferromagnetic $\mathrm{spin}\ensuremath{-}\frac{1}{2}$ chain. Comparison to state of the art computational techniques shows excellent agreement over a wide temperature range. Our findings hence demonstrate the possibility to quantitatively predict coherent behavior at elevated temperatures in quantum magnets.
Various forms of antiferromagnetic exchange interaction among quantized spins in one-dimensional and quasi-one-dimensional lattices are examined. Primary results are reported in two real compounds, the sodium vanadate NaV2O5 and the copper germanate CuGeO3, and in a class of compounds of real materials modeled as dimerized antiferromagnetically coupled spin-1/2 chains susceptible to spin-1 impurity doping and that include such examples as the strontium cuprate Sr14Cu24O41 and vanadium pyrophosphate (VO)2P2O7. Sodium vanadate, NaV2O5, a quarter-filled two-leg ladder compound that was originally thought to be composed of magnetic legs and nonmagnetic legs was subsequently shown to be a charge ordered system below room temperature. Initial models of the material as isolated antiferromagnetically coupled spin-1/2 chains can be mapped to the subsequently resolved magnetic system of the charge ordered state with the spins on molecular orbitals of V-O-V rungs antiferromagentically coupled between neighboring rungs either on the same ladder or on neighboring ladders. Comparing the model's dynamic structure factor to inelastic neutron scattering data could distinguish between the proposed spin coupling schemes and consequently reveal the details of the interaction between the lattice and the "zig-zag" charge density as well as the magnetic stabilization of the low temperature phase. Copper germanate, the first and only known inorganic spin-Peierls compound, exhibits a strong temperature dependent exchange coupling pattern among the spin-1/2 Cu2+ chains. Above the spin-Peierls transition temperature an unmodulated antiferromagnetic nearest neighbor exchange interaction J1 competes with an antiferromagnetic next nearest neighbor interaction J2. The next nearest neighbor exchange represents an effective coupling equivalent to the net effect of all longer range exchange interactions. This frustration to the nearest neighbor spin exchange produces a distinctive magnetic susceptibility χ (T) much different from the Bonner-Fisher susceptibility of the spin-1/2 Heisenberg chain with nearest neighbor antiferromagnetic exchange only. The ratio of the second to first nearest neighbor couplings α = J2/J1 ≈ 0.36 is sufficient to open a spontaneous gap in the spin-wave excitation spectrum at low temperatures. Below TSP = 14K, the dynamical structure factor is used to fit the dimerization δ and the exchange interactions J1 and J2 to the inelastic neutron scattering data of CuGeO3 at T = 10K. It is found that both δ and α increase significantly at lower temperatures, relative to the values obtained in the high temperature phase and at the onset of dimeration at 14 K. Static structure factor calculations how Scattering inconsistent with the δ−J1−J2 model and can be attributed primarily to the phonon degrees of freedom but possibly also to the couplings between chains in the b and a directions of the crystal lattice. Structurally dimerized compounds of antiferromagnetic spin-1/2 chains possess dynamic structure factor and magnetic susceptibility features that are very sensitive to doping with magnetic and nonmagnetic impurities. It is shown that the effects of spin-1 impurities are very similar to those of nonmagnetic (S = 0) impurities if the coupling between impurity and native spin is about the same magnitude as or larger than between native S = 1/2 spins. The microscopic origins of the similarity can be appreciated with the consideration that neighboring spins to the impurity find it more energetically favorable to couple to the impurity than the other spins of the lattice. Thus the spin-1 impurity and its neighboring S = 1/2 spins decouple from the lattice, creating a nonmagnetic break in the chain. The spins that now observe a nonmagnetic cluster on one side can couple to the S = 1/2 spins on the other side with a higher AF correlation than in the pure compound since they do not have to have a fluctuating dimer resonating between two neighbors. Such enhancements to the local correlations can stabilize the global AF order in one dimensional compounds as shown in theoretical and experimental studies of CuGeO3. ED calculations of the dynamic structure factor show that S(q, ω) developes states with ω = 0 in the gap at q = π. Magnetic susceptibilites in the presense of spin-1 impurities were obtained for 80 site chains by QMC simulations and for 16 site chains by ED calculations. An impurity concentration-dependent second peak in the low temperature region reveals an increasing second maximum with T as observed in doped copper germanates and suggests that the results of the study are applicable even to phonon mediated dimerization. This is not immediately apparent because spin-phonon coupling could distort the dimerization patterns. However, experimental and theoretical results show that elastic coupling between chains can stabilize the dimerization pattern due to the impurities and the results will still apply.
We study electronic and magnetic properties of the quasi-one-dimensional spin-12\frac{1}{2}21​ magnet Ba3Cu3Sc4O12{\mathrm{Ba}}_{3}{\mathrm{Cu}}_{3}{\mathrm{Sc}}_{4}{\mathrm{O}}_{12}Ba3​Cu3​Sc4​O12​ with a distinct orthogonal connectivity of CuO4{\mathrm{CuO}}_{4}CuO4​ plaquettes. An effective low-energy model taking into account spin-orbit coupling was constructed by means of first-principles calculations. On this basis, a complete microscopic magnetic model of Ba3Cu3Sc4O12{\mathrm{Ba}}_{3}{\mathrm{Cu}}_{3}{\mathrm{Sc}}_{4}{\mathrm{O}}_{12}Ba3​Cu3​Sc4​O12​, including symmetric and antisymmetric anisotropic exchange interactions, is derived. The anisotropic exchanges are obtained from a distinct first-principles numerical scheme combining, on one hand, the local density approximation taking into account spin-orbit coupling, and, on the other hand, a projection procedure along with the microscopic theory by Moriya [Phys. Rev. 120, 91 (1960)]. The resulting tensors of the symmetric anisotropy favor collinear magnetic order along the structural chains with the leading ferromagnetic coupling ${J}_{1}\ensuremath{\simeq}\ensuremath{-}9.88$ meV. The interchain interactions ${J}_{8}\ensuremath{\simeq}0.21$ and ${J}_{5}\ensuremath{\simeq}0.093$ meV are antiferromagnetic. Quantum Monte Carlo simulations demonstrate that the proposed model reproduces the experimental Neel temperature, magnetization, and magnetic susceptibility data. The modeling of neutron-diffraction data reveals an important role of the covalent Cu-O bonding in Ba3Cu3Sc4O12{\mathrm{Ba}}_{3}{\mathrm{Cu}}_{3}{\mathrm{Sc}}_{4}{\mathrm{O}}_{12}Ba3​Cu3​Sc4​O12​.
Various static spin-correlation functions and the weights of the spin excitations, or collective normal modes, in the van Hove response function, observed in neutron scattering experiments, are calculated as a function of temperature for a model quantum-spin chain. The spins interact through an isotropic Heisenberg exchange that extends to nearest-neighbour spins. In our model, spins of magnitude 1/2 form a dimerized chain with alternating exchange interactions. We explore the static and dynamic properties for ferromagnetic and antiferromagnetic exchange interactions. Results for the various properties are shown to be exact in the limit of a high temperature, and we argue that the results are very good at low temperatures. Unlike the case for linear spin-wave theory, the results are also exact in the limit of strong dimerization, i.e. non-interacting coupled pairs of spins.
We have performed inelastic neutron scattering on a single crystal sample of Sr14Cu24O41{\mathrm{Sr}}_{14}{\mathrm{Cu}}_{24}{\mathrm{O}}_{41}Sr14​Cu24​O41​ to study the spin dynamics of the Cu2O3{\mathrm{Cu}}_{2}{\mathrm{O}}_{3}Cu2​O3​ spin ladder layers and CuO2{\mathrm{CuO}}_{2}CuO2​ chains. Our data are best fitted with a dispersion which has a spin gap of $32.5\ifmmode\pm\else\textpm\fi{}0.1\mathrm{meV}$ and a maximum of $193.5\ifmmode\pm\else\textpm\fi{}2.4\mathrm{meV}$, consistent with a coupling along the ladders, ${J}_{\ensuremath{\parallel}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}130\phantom{\rule{0ex}{0ex}}\mathrm{meV}$ and a rung coupling ${J}_{\ensuremath{\perp}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}72\mathrm{meV}$. Excitations with an energy transfer of approximately 11.5 meV arise from a dimer chain with an antiferromagnetic intradimer coupling J1=11.2meV{J}_{1}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}11.2\mathrm{meV}J1​=11.2meV between next-nearest-neighbor Cu ions, and a ferromagnetic interdimer coupling ${J}_{2}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}1.1\mathrm{meV}$. The dimer chains have a periodicity of five units.
Using Wannier function formulation and total energy calculations by first-principles density functional theory (DFT), we derive the underlying spin model of a recently synthesized compound, Cs2CuAl4O8{\mathrm{Cs}}_{2}{\mathrm{CuAl}}_{4}{\mathrm{O}}_{8}Cs2​CuAl4​O8​, having zeolitelike network structure. The computed magnetic interactions show that the interchain Cu-Cu interactions are negligibly small compared to intrachain Cu-Cu interactions, thus characterizing Cs2CuAl4O8{\mathrm{Cs}}_{2}{\mathrm{CuAl}}_{4}{\mathrm{O}}_{8}Cs2​CuAl4​O8​ as a prototypical one-dimensional (1D) spin-12\frac{1}{2}21​ system. Interestingly, the DFT-derived 1D spin model features a combination of alternating ferromagnetic-antiferromagnetic interactions, together with the presence of both nearest- and next-nearest-neighbor interactions, making it an unprecedented case. The solution of the derived spin model of the compound using the quantum Monte Carlo technique shows reasonably good agreement with the experimental susceptibility data, measured in the presence of the magnetic field. The presence of spin gap is suggested by quantum Monte Carlo simulations in the zero-field condition, which is cross-checked by a more rigorous exact diagonalization study. Motivated by the intricacy of the derived spin model, we further examine the ground-state properties of this model in the parameter space of exchange interactions, which shows the possibility of driving quantum phase transition between gapped and gapless spin excitation. Our study is expected to shed light on the fascinating world of 1D quantum spin systems.