Pub Date : 2022-08-17DOI: 10.15625/0868-3166/16890
Tong Sy Tien
In this paper, the temperature-dependent extended X-ray absorption fine structure (EXAFS) of distorted crystalline cadmium has been analyzed using an efficient calculation-model. The analysis procedure is based on evaluating the influence of temperature on the phase shift and amplitude reduction of EXAFS oscillation that is expressed in terms of the EXAFS Debye-Waller factor. The anharmonic EXAFS cumulants are calculated by expanding the anharmonic correlated Debye model based on the anharmonic effective potential that depends on the structural characteristics of distorted crystalline cadmium. The numerical results satisfy well with those obtained using the experimental data and other models at various temperatures. The obtained results indicate that this theoretical model is useful for calculating and analyzing the experimental EXAFS data of distorted crystalline metals.
{"title":"Analysis of Temperature-dependent Extended X-ray Absorption Fine Structure Oscillation of Distorted Crystalline Cadmium","authors":"Tong Sy Tien","doi":"10.15625/0868-3166/16890","DOIUrl":"https://doi.org/10.15625/0868-3166/16890","url":null,"abstract":"In this paper, the temperature-dependent extended X-ray absorption fine structure (EXAFS) of distorted crystalline cadmium has been analyzed using an efficient calculation-model. The analysis procedure is based on evaluating the influence of temperature on the phase shift and amplitude reduction of EXAFS oscillation that is expressed in terms of the EXAFS Debye-Waller factor. The anharmonic EXAFS cumulants are calculated by expanding the anharmonic correlated Debye model based on the anharmonic effective potential that depends on the structural characteristics of distorted crystalline cadmium. The numerical results satisfy well with those obtained using the experimental data and other models at various temperatures. The obtained results indicate that this theoretical model is useful for calculating and analyzing the experimental EXAFS data of distorted crystalline metals.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91151025","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}
Pub Date : 2022-08-09DOI: 10.15625/0868-3166/17173
D. Trung, H. Bui Van, Thi Thanh Bao Nguyen, Thi Kim Oanh Vu, Xuan Tu Nguyen, V. Phung, Hong Minh Pham
Monitoring the concentration and distribution of nitrogen dioxide NO2 in urban environment is of great interest because of the importance of this gaseous pollutant in affecting air quality. In this paper we present the development of a multi-axis differential optical absorption spectroscopy instrument capable of sensitively detecting NO2. The passive instrument collects the sun light scattered by the air molecules and aerosols in the atmosphere and measures the spectrum using a highly sensitive portable spectrometer. The viewing direction of the instrument is controlled through a motor and can be changed continuously. Data analysis of the measured spectra allows us to simultaneously determine the differential scant column density of NO2 and oxygen dimer O4. From the accurately known concentration of O4, the effective optical path length of scattered sun light near the horizontal direction could be derived, which in turn provides an estimate the concentration of NO2. The measured data show that the concentration of NO2 in Hanoi is in the range ~1.5 ppb. We also present the detection of formaldehyde HCHO and possible detection of glyoxal CHOCHO. Our sensitive instrument opens up the possibility to monitor the concentration of other molecular species of interest in urban environment of Hanoi.
{"title":"Estimation of Atmospheric NO(_2) Volume Mixing Ratio in Hanoi Using Multi-axis Differential Optical Absorption Spectroscopy Technique","authors":"D. Trung, H. Bui Van, Thi Thanh Bao Nguyen, Thi Kim Oanh Vu, Xuan Tu Nguyen, V. Phung, Hong Minh Pham","doi":"10.15625/0868-3166/17173","DOIUrl":"https://doi.org/10.15625/0868-3166/17173","url":null,"abstract":"Monitoring the concentration and distribution of nitrogen dioxide NO2 in urban environment is of great interest because of the importance of this gaseous pollutant in affecting air quality. In this paper we present the development of a multi-axis differential optical absorption spectroscopy instrument capable of sensitively detecting NO2. The passive instrument collects the sun light scattered by the air molecules and aerosols in the atmosphere and measures the spectrum using a highly sensitive portable spectrometer. The viewing direction of the instrument is controlled through a motor and can be changed continuously. Data analysis of the measured spectra allows us to simultaneously determine the differential scant column density of NO2 and oxygen dimer O4. From the accurately known concentration of O4, the effective optical path length of scattered sun light near the horizontal direction could be derived, which in turn provides an estimate the concentration of NO2. The measured data show that the concentration of NO2 in Hanoi is in the range ~1.5 ppb. We also present the detection of formaldehyde HCHO and possible detection of glyoxal CHOCHO. Our sensitive instrument opens up the possibility to monitor the concentration of other molecular species of interest in urban environment of Hanoi.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"119 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87987052","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}
Pub Date : 2022-07-25DOI: 10.15625/0868-3166/17121
D. Ho, V. B. Chu, V. Le, Van Chin Hoang, Thi Thao Nguyen, V. Hoang, Longgui Cao
We report on numerical simulation and experimental study of the supercontinuum (SC) generation in the anomalous dispersion region of photonic crystal fiber (PCF). The results show that a flat and stable spectrum with bandwidth of 130 nm around the central pump wavelength was achieved with an input power of 4.0 W. Although the measured spectrum is slightly different from the numerical ones, a good consistency can be recognized in the major sideband positions and spectral width. In addition, the chromatic dispersion of air silica PCF was measured at visible and near-infrared wavelengths using the Mach-Zehnder interferometer configuration and then verified by comparison with simulated results.
{"title":"Silica-based Photonic Crystal Fiber for Supercontinuum Generation in the Anomalous Dispersion Region: Measurement and Simulation","authors":"D. Ho, V. B. Chu, V. Le, Van Chin Hoang, Thi Thao Nguyen, V. Hoang, Longgui Cao","doi":"10.15625/0868-3166/17121","DOIUrl":"https://doi.org/10.15625/0868-3166/17121","url":null,"abstract":"We report on numerical simulation and experimental study of the supercontinuum (SC) generation in the anomalous dispersion region of photonic crystal fiber (PCF). The results show that a flat and stable spectrum with bandwidth of 130 nm around the central pump wavelength was achieved with an input power of 4.0 W. Although the measured spectrum is slightly different from the numerical ones, a good consistency can be recognized in the major sideband positions and spectral width. In addition, the chromatic dispersion of air silica PCF was measured at visible and near-infrared wavelengths using the Mach-Zehnder interferometer configuration and then verified by comparison with simulated results.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":" 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91413137","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}
Pub Date : 2022-07-07DOI: 10.15625/0868-3166/16787
Thu Trang Tran, Xuan Hoa Vu, Thi Thu Ha Pham, Trọng-Nghĩa Nguyễn, D. D. Nguyen
In this study, a surface-enhanced Raman scattering (SERS) substrate based on an octahedral cuprous oxide (Cu2O) nanostructure to probe methylene blue (MB) molecules as an analyte chemical has been implemented. Octahedral Cu2O nanocrystals were synthesized by a novel hydrothermal process using only ethylene glycol as both a reductant and organic solvent. The characteristics of Cu2O nanocrystals were well recognized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), FTIR, and Raman spectroscopy. The mechanism of the SERS surface has been thoroughly investigated and has been shown to involve the contributions of both surface plasmon resonance and charge transfer effects. Using a simple collection rule for SERS bands, the portion of charge transfer processes was estimated to be about 46%.
{"title":"Study of Charge Transfer Contribution to Surface-Enhanced Raman Scattering Activity of Cu(_2)O Nano-octahedral Substrate","authors":"Thu Trang Tran, Xuan Hoa Vu, Thi Thu Ha Pham, Trọng-Nghĩa Nguyễn, D. D. Nguyen","doi":"10.15625/0868-3166/16787","DOIUrl":"https://doi.org/10.15625/0868-3166/16787","url":null,"abstract":"In this study, a surface-enhanced Raman scattering (SERS) substrate based on an octahedral cuprous oxide (Cu2O) nanostructure to probe methylene blue (MB) molecules as an analyte chemical has been implemented. Octahedral Cu2O nanocrystals were synthesized by a novel hydrothermal process using only ethylene glycol as both a reductant and organic solvent. The characteristics of Cu2O nanocrystals were well recognized by scanning electron microscope (SEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), FTIR, and Raman spectroscopy. The mechanism of the SERS surface has been thoroughly investigated and has been shown to involve the contributions of both surface plasmon resonance and charge transfer effects. Using a simple collection rule for SERS bands, the portion of charge transfer processes was estimated to be about 46%.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"56 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91392225","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}
Pub Date : 2022-07-05DOI: 10.15625/0868-3166/16674
N. Tien, Dang Minh Triet, Pham Thi Bich Thao
We performed density functional theory based first-principles calculations to investigate the opto-electronic properties of small ZnO2 nanoparticles. We have shown that these ZnO2 nanoparticles can exhibit either semiconductor or metallic properties depending on the morphology and sizes of the nanoparticles defined by Miller indices. The absorption spectra computedfrom the real and imaginary parts of the dielectric functions demonstrate that these nanoparticles exhibit rich optical features with highly spatial anisotropy in the visible light range, suggesting that these newly obtained configurations strongly influence the electronic structures of ZnO2 nanoparticles. Our results propose the potential application of using Zinc peroxide nanopariclesas prospective building blocks for developing early diagnosis nanodevices in drug industry.
{"title":"Opto-electronic Properties of Small ZnO(_2) Nanoparticles: First-Principles Insights","authors":"N. Tien, Dang Minh Triet, Pham Thi Bich Thao","doi":"10.15625/0868-3166/16674","DOIUrl":"https://doi.org/10.15625/0868-3166/16674","url":null,"abstract":"We performed density functional theory based first-principles calculations to investigate the opto-electronic properties of small ZnO2 nanoparticles. We have shown that these ZnO2 nanoparticles can exhibit either semiconductor or metallic properties depending on the morphology and sizes of the nanoparticles defined by Miller indices. The absorption spectra computedfrom the real and imaginary parts of the dielectric functions demonstrate that these nanoparticles exhibit rich optical features with highly spatial anisotropy in the visible light range, suggesting that these newly obtained configurations strongly influence the electronic structures of ZnO2 nanoparticles. Our results propose the potential application of using Zinc peroxide nanopariclesas prospective building blocks for developing early diagnosis nanodevices in drug industry.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87680390","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}
Pub Date : 2022-06-22DOI: 10.15625/0868-3166/16867
Thi Thu Giang Luu, Q. Do, M. Tran, T. Nguyen, D. H. Nguyen, T. Pham
MoS2 material attracts a great attention from researchers due to its graphene-like structure and the bandgap difference between its hexagonal monolayer and bulks. Recently, ZnO/MoS2 heterostructures have been received significant interest due to their distinguished properties. In this study, one-dimensional ZnO and ZnO/MoS2 heterostructures were successfully synthesized by a thermal co-evaporation method. Compare with ZnO, the band-to-band emission of ZnO/MoS2 heterostructures establishes a “blueshift” towards a shorter wavelength. It could be explained by the lattice strain in ZnO/MoS2 heterostructures due to the difference of primitive cell of ZnO and MoS2. Additionally, the quench in the visible region of the PL spectrum of ZnO/MoS2 heterostructures also explains the reduction of the defect in ZnO due to the presence of MoS2.
{"title":"Optical Properties of 1D ZnO/MoS(_2) Heterostructures Synthesized by Thermal Evaporation Method","authors":"Thi Thu Giang Luu, Q. Do, M. Tran, T. Nguyen, D. H. Nguyen, T. Pham","doi":"10.15625/0868-3166/16867","DOIUrl":"https://doi.org/10.15625/0868-3166/16867","url":null,"abstract":"MoS2 material attracts a great attention from researchers due to its graphene-like structure and the bandgap difference between its hexagonal monolayer and bulks. Recently, ZnO/MoS2 heterostructures have been received significant interest due to their distinguished properties. In this study, one-dimensional ZnO and ZnO/MoS2 heterostructures were successfully synthesized by a thermal co-evaporation method. Compare with ZnO, the band-to-band emission of ZnO/MoS2 heterostructures establishes a “blueshift” towards a shorter wavelength. It could be explained by the lattice strain in ZnO/MoS2 heterostructures due to the difference of primitive cell of ZnO and MoS2. Additionally, the quench in the visible region of the PL spectrum of ZnO/MoS2 heterostructures also explains the reduction of the defect in ZnO due to the presence of MoS2.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79535867","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}
Pub Date : 2022-06-14DOI: 10.15625/0868-3166/17169
T. Nguyen, M. Kiselev
We revisit a model describing Seebeck effect on a weak link between two charge Kondo circuits, which has been proposed in the [Phys. Rev. B 97 (2018) 085403]. We calculate the thermoelectric coefficients in the perturbation theory assuming smallness of the reflection amplitudes of the quantum point contacts. We focus on the linear response equations for the heat conductance in three different scenarios as: Fermi liquid vs Fermi liquid, Fermi liquid vs non-Fermi liquid, non-Fermi liquid vs non-Fermi liquid. The oscillations of the heat conductance as a function of the gate voltage of each quantum dot are analysed in both Fermi liquid and non-Fermi liquid regimes. We discuss possible experimental realizations of the model to observe the signatures of the non-Fermi liquid behaviour in the heat conductance measurements.
{"title":"Heat Conductance Oscillations in Two Weakly Connected Charge Kondo Circuits","authors":"T. Nguyen, M. Kiselev","doi":"10.15625/0868-3166/17169","DOIUrl":"https://doi.org/10.15625/0868-3166/17169","url":null,"abstract":"We revisit a model describing Seebeck effect on a weak link between two charge Kondo circuits, which has been proposed in the [Phys. Rev. B 97 (2018) 085403]. We calculate the thermoelectric coefficients in the perturbation theory assuming smallness of the reflection amplitudes of the quantum point contacts. We focus on the linear response equations for the heat conductance in three different scenarios as: Fermi liquid vs Fermi liquid, Fermi liquid vs non-Fermi liquid, non-Fermi liquid vs non-Fermi liquid. The oscillations of the heat conductance as a function of the gate voltage of each quantum dot are analysed in both Fermi liquid and non-Fermi liquid regimes. We discuss possible experimental realizations of the model to observe the signatures of the non-Fermi liquid behaviour in the heat conductance measurements.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83072042","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}
Pub Date : 2022-06-03DOI: 10.15625/0868-3166/16754
N. L. Pham, T. Luu, Thi Tuyet Mai Nguyen, V. Pham, H. L. Nguyen, C. Nguyen
Different tungsten oxide nanocrystals were synthesized via facile hydrothermal process – one-step and free of additives - at different reaction temperatures and a highly acidic environment. The phase transformation of samples, followed by the change of morphology and optical properties, was observed as the reaction temperature varied from room temperature to 220oC. The crystal phase transformed from monoclinic WO3∙2H2O to orthorhombic WO3∙H2O, then to monoclinic WO3 as the reaction temperature increased from room temperature to 100 ⁰C, then to 220 ⁰C. Corresponding to the phase transformation, the optical bandgap increased from 2.43 eV to 2.71 eV, and the morphology varied from nanoplate to nanocuboid. The effect of the reaction temperature on the phase transformation was assigned to the dehydration process, which became stronger as the reaction temperature increased. These results gave an insight into the phase transformation and implied a simple method for manipulating the crystal phase and morphology of tungsten oxide nanostructure for various applications.
{"title":"Temperature-mediated Phase Transformation and Optical Properties of Tungsten Oxide Nanostructures Prepared by Facile Hydrothermal Method","authors":"N. L. Pham, T. Luu, Thi Tuyet Mai Nguyen, V. Pham, H. L. Nguyen, C. Nguyen","doi":"10.15625/0868-3166/16754","DOIUrl":"https://doi.org/10.15625/0868-3166/16754","url":null,"abstract":"Different tungsten oxide nanocrystals were synthesized via facile hydrothermal process – one-step and free of additives - at different reaction temperatures and a highly acidic environment. The phase transformation of samples, followed by the change of morphology and optical properties, was observed as the reaction temperature varied from room temperature to 220oC. The crystal phase transformed from monoclinic WO3∙2H2O to orthorhombic WO3∙H2O, then to monoclinic WO3 as the reaction temperature increased from room temperature to 100 ⁰C, then to 220 ⁰C. Corresponding to the phase transformation, the optical bandgap increased from 2.43 eV to 2.71 eV, and the morphology varied from nanoplate to nanocuboid. The effect of the reaction temperature on the phase transformation was assigned to the dehydration process, which became stronger as the reaction temperature increased. These results gave an insight into the phase transformation and implied a simple method for manipulating the crystal phase and morphology of tungsten oxide nanostructure for various applications.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"AES-21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84587303","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}
Pub Date : 2022-06-01DOI: 10.15625/0868-3166/16829
Thi Tuyet Ngan Nguyen, Thanh Giang Bui, D. T. Nguyen, Duc Thanh Nguyen, H. Nguyen, T. H. Nguyen, Thanh Binh Dang, T. T. Vu
In this work, pyrolytic carbon electrodes were prepared through pyrolysis of well-patterned AZ 1505 positive photoresist films. The designed electrodes firstly were prepared via photolithography technique, then the polymer was thermally broken-down into carbon skeletons in an oxygen-free environment using pyrolysis technique. The effect of the highest temperature and ramping rate on the electrical properties of the carbon films were investigated. The results show that the pyrolysis process was optimal at the ramping rate of 3 °C/minute, annealing temperature of 900 °C, and annealing time of one hour. The lowest resistivity was obtained at 6.3 ´ 10-5 Wm for pyrolytic films prepared at the optimal pyrolysis conditions. Electrochemical measurements confirm the potential of this electrode for electrochemical sensing applications.
{"title":"Pyrolytic Carbon Electrodes and Their Potential Application in Electrochemical Sensors","authors":"Thi Tuyet Ngan Nguyen, Thanh Giang Bui, D. T. Nguyen, Duc Thanh Nguyen, H. Nguyen, T. H. Nguyen, Thanh Binh Dang, T. T. Vu","doi":"10.15625/0868-3166/16829","DOIUrl":"https://doi.org/10.15625/0868-3166/16829","url":null,"abstract":"In this work, pyrolytic carbon electrodes were prepared through pyrolysis of well-patterned AZ 1505 positive photoresist films. The designed electrodes firstly were prepared via photolithography technique, then the polymer was thermally broken-down into carbon skeletons in an oxygen-free environment using pyrolysis technique. The effect of the highest temperature and ramping rate on the electrical properties of the carbon films were investigated. The results show that the pyrolysis process was optimal at the ramping rate of 3 °C/minute, annealing temperature of 900 °C, and annealing time of one hour. The lowest resistivity was obtained at 6.3 ´ 10-5 Wm for pyrolytic films prepared at the optimal pyrolysis conditions. Electrochemical measurements confirm the potential of this electrode for electrochemical sensing applications.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76235368","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}
Pub Date : 2022-05-11DOI: 10.15625/0868-3166/16748
T. Do
The condensate state of excitons in semimetal/semiconductor materials has been considered by analyzing the excitonic susceptibility function in the 2D extended Falicov-Kimbol model including electron-phonon interaction. The excitonic susceptibility in the system has calculated by using the Hartree-Fock approximation. From numerical results, we have set up phase diagrams ofthe excitonic condensate state. Phase diagrams confirm that the electron-phonon coupling plays an important role as well as the Coulomb attraction does in establishing the excitonic condensed phase at low temperature. The condensate phase of excitons is found within a limited range of the Coulomb attraction as the electron-phonon coupling is large enough. Depending on theelectron-phonon coupling and the Coulomb attraction, the BCS-BEC crossover of the excitonic condensation phase has also been pointed out.
{"title":"The Excitonic Susceptibility Function in Semimetal/semiconductor Materials: Formation of the Excitonic Condensate State","authors":"T. Do","doi":"10.15625/0868-3166/16748","DOIUrl":"https://doi.org/10.15625/0868-3166/16748","url":null,"abstract":"The condensate state of excitons in semimetal/semiconductor materials has been considered by analyzing the excitonic susceptibility function in the 2D extended Falicov-Kimbol model including electron-phonon interaction. The excitonic susceptibility in the system has calculated by using the Hartree-Fock approximation. From numerical results, we have set up phase diagrams ofthe excitonic condensate state. Phase diagrams confirm that the electron-phonon coupling plays an important role as well as the Coulomb attraction does in establishing the excitonic condensed phase at low temperature. The condensate phase of excitons is found within a limited range of the Coulomb attraction as the electron-phonon coupling is large enough. Depending on theelectron-phonon coupling and the Coulomb attraction, the BCS-BEC crossover of the excitonic condensation phase has also been pointed out.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"30 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84431857","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}
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