Pub Date : 2022-05-08DOI: 10.15625/0868-3166/17064
N. An
Methods for two distant parties to exchange their secret messages usingsingle photons are considered. There existed several such methods but theyare either insecure or face with information leakage problem. Recently, Ye textit{et al.} [Quantum Inf. Process. 20 (2021) 209] have reported a methodusing single photons in both polarization and spatial degrees of freedomthat is both efficient and resistant from information leakage. However, thismethod is not so feasible as it has specific limitations, namely, itrequires availability of quantum memory and high classical communicationcost. We propose in this paper a new method to overcome the above-saidlimitations. Our method is also efficient because we also use single photonsin two degrees of freedom. However, the encoding operation in our method ismodified so that no quantum memory is demanded at all and the execution ofour method is simpler compared to the method of Ye textit{et al.}.Moreover, the cost of classical communication in our method is 50% cheaperthan that in the method of Ye textit{et al.} Therefore, our method provesto be feasible, simple and economical that could be realized by means ofcurrent technologies.
{"title":"SECURE INFORMATION EXCHANGE WITHOUT PRIOR KEY DISTRIBUTION VIA SINGLE-PHOTON HYPERSTATES","authors":"N. An","doi":"10.15625/0868-3166/17064","DOIUrl":"https://doi.org/10.15625/0868-3166/17064","url":null,"abstract":"Methods for two distant parties to exchange their secret messages usingsingle photons are considered. There existed several such methods but theyare either insecure or face with information leakage problem. Recently, Ye textit{et al.} [Quantum Inf. Process. 20 (2021) 209] have reported a methodusing single photons in both polarization and spatial degrees of freedomthat is both efficient and resistant from information leakage. However, thismethod is not so feasible as it has specific limitations, namely, itrequires availability of quantum memory and high classical communicationcost. We propose in this paper a new method to overcome the above-saidlimitations. Our method is also efficient because we also use single photonsin two degrees of freedom. However, the encoding operation in our method ismodified so that no quantum memory is demanded at all and the execution ofour method is simpler compared to the method of Ye textit{et al.}.Moreover, the cost of classical communication in our method is 50% cheaperthan that in the method of Ye textit{et al.} Therefore, our method provesto be feasible, simple and economical that could be realized by means ofcurrent technologies.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86767524","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 : 2022-04-29DOI: 10.15625/0868-3166/16830
Nhung T T Nguyen, P. Bui, T. X. Hoang
The effects of inert spherical crowders on the melting temperature and the folding stability of small globular proteins are investigated by using molecular dynamics simulations with a Gō-like model for the proteins. The energy parameter in the Gō-like model is obtained individually for each protein by matching the model’s melting temperature to the experimental meltingtemperature in the absence of crowders. It is shown that both the melting temperature and the folding stability of protein increase in the presence of the crowders. Specifically, as the crowders’ volume fraction φc increases from 0 to 0.4 the melting temperature increases by more than 20 Kelvins, whereas the folding stability is enhanced by up to ∼3.6 kcal/mol depending on the protein and the temperature. At room temperature (300 K), the stability enhancement is 1.2–1.4 kcal/mol, which is close to prior experimental data. It is also shown that the dependence of the folding free energy change on φc can be fitted well to the scaled particle theory by assuming a linear dependence of the effective size of the unfolded state on φc .
{"title":"Effects of macromolecular crowding on folding of small globular proteins","authors":"Nhung T T Nguyen, P. Bui, T. X. Hoang","doi":"10.15625/0868-3166/16830","DOIUrl":"https://doi.org/10.15625/0868-3166/16830","url":null,"abstract":"The effects of inert spherical crowders on the melting temperature and the folding stability of small globular proteins are investigated by using molecular dynamics simulations with a Gō-like model for the proteins. The energy parameter in the Gō-like model is obtained individually for each protein by matching the model’s melting temperature to the experimental meltingtemperature in the absence of crowders. It is shown that both the melting temperature and the folding stability of protein increase in the presence of the crowders. Specifically, as the crowders’ volume fraction φc increases from 0 to 0.4 the melting temperature increases by more than 20 Kelvins, whereas the folding stability is enhanced by up to ∼3.6 kcal/mol depending on the protein and the temperature. At room temperature (300 K), the stability enhancement is 1.2–1.4 kcal/mol, which is close to prior experimental data. It is also shown that the dependence of the folding free energy change on φc can be fitted well to the scaled particle theory by assuming a linear dependence of the effective size of the unfolded state on φc .","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-04-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85241617","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 : 2022-03-27DOI: 10.15625/0868-3166/15924
Vu Thi Ngoc Thuy, C. Hoang
Guiding plasmon waves is based on dielectric/metal interfaces. The wedge-shaped interface shows an excellent capacity in the tight lightwave confinement at deep-subwavelength propagation mode size. Several types of metals have also been investigated for guiding plasmon waves. Among them, the Ag metal shows a plasmon wave guiding ability superior to other metals, however, it is sensitive to the operating medium and is easily oxidized. To overcome these drawbacks, the Ag wedge covered by a protective thin oxide layer is proposed. Numerically investigated results show that the propagation length of the Ag wedge covered by a protective thin silicon dioxide layer can be enhanced by a factor of 7.5 while its figure of merit is at least 1.7 times larger than that of the Au wedge waveguide. The advantage of the proposed interface is potential for developing plasmonic waveguide components.
{"title":"Plasmon Wave Propagation Property of Metal Wedge Plasmonic Waveguides Covered by a Protective Oxide Layer","authors":"Vu Thi Ngoc Thuy, C. Hoang","doi":"10.15625/0868-3166/15924","DOIUrl":"https://doi.org/10.15625/0868-3166/15924","url":null,"abstract":"Guiding plasmon waves is based on dielectric/metal interfaces. The wedge-shaped interface shows an excellent capacity in the tight lightwave confinement at deep-subwavelength propagation mode size. Several types of metals have also been investigated for guiding plasmon waves. Among them, the Ag metal shows a plasmon wave guiding ability superior to other metals, however, it is sensitive to the operating medium and is easily oxidized. To overcome these drawbacks, the Ag wedge covered by a protective thin oxide layer is proposed. Numerically investigated results show that the propagation length of the Ag wedge covered by a protective thin silicon dioxide layer can be enhanced by a factor of 7.5 while its figure of merit is at least 1.7 times larger than that of the Au wedge waveguide. The advantage of the proposed interface is potential for developing plasmonic waveguide components.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"137 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77222267","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 : 2022-03-27DOI: 10.15625/0868-3166/16737
Thi Tuyet Ngan Nguyen, T. T. Vu
In this work, an enzymatic liquid-gated field-effect-transistor sensor based on chemically reduced graphene oxide film was develop for determination of acetylthiocholine in aqueous conditions. The device was designed with interdigitated electrode configuration and then manufactured by combining lithography and chemical vapor deposition techniques in clean room. Graphene oxide material (prepared by Hummer method) was chemically reduced using a strong reducing agent hydrazine, and then drop-casted onto the channel region. The results have demonstrated a successful reduction of graphene oxide with clearly shifting of 02 characteristic peaks comparing with graphene oxide. Consequently, the transfer curve of as-prepared reduced graphene oxide based transistor exhibits ambipolar characteristics with a V-shape. Acetylcholinesterase was immobilized on top of reduced graphene oxide film with the aid of glutaraldehyde trapping agent. It was found that the release of proton from enzymatic hydrolysis of acetylthiocholine has caused significant variation in charge concentration and mobility in the channel, thus generated a significant blue shift in position of Dirac point on ambipolar curve. The developed sensor exhibits good sensing performances with LOD of 250 µM in concentration range 0 – 0.8 mM.
{"title":"Liquid-gated Field-effect-transistor Based on Chemically Reduced Graphene Oxide for Sensing Neurotransmitter Acetylthiocholine","authors":"Thi Tuyet Ngan Nguyen, T. T. Vu","doi":"10.15625/0868-3166/16737","DOIUrl":"https://doi.org/10.15625/0868-3166/16737","url":null,"abstract":"In this work, an enzymatic liquid-gated field-effect-transistor sensor based on chemically reduced graphene oxide film was develop for determination of acetylthiocholine in aqueous conditions. The device was designed with interdigitated electrode configuration and then manufactured by combining lithography and chemical vapor deposition techniques in clean room. Graphene oxide material (prepared by Hummer method) was chemically reduced using a strong reducing agent hydrazine, and then drop-casted onto the channel region. The results have demonstrated a successful reduction of graphene oxide with clearly shifting of 02 characteristic peaks comparing with graphene oxide. Consequently, the transfer curve of as-prepared reduced graphene oxide based transistor exhibits ambipolar characteristics with a V-shape. Acetylcholinesterase was immobilized on top of reduced graphene oxide film with the aid of glutaraldehyde trapping agent. It was found that the release of proton from enzymatic hydrolysis of acetylthiocholine has caused significant variation in charge concentration and mobility in the channel, thus generated a significant blue shift in position of Dirac point on ambipolar curve. The developed sensor exhibits good sensing performances with LOD of 250 µM in concentration range 0 – 0.8 mM.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89849090","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 : 2022-03-27DOI: 10.15625/0868-3166/16541
Cam Thi Hong Hoang, T. Ha, V. D. Pham, Q. M. Ngo
This work reports the optical properties of surface plasmon resonance (SPR) based on the metal-insulator-metal (MIM) structure towards a refractive index sensor. The MIM-SPR structure operating near infrared region consists of lateral periodicity of subwavelength gold patterns placed on a stack of thin silica spacer and silver film (acting as a reflector) on a silicon substrate. The reflection spectra and the electric field distributions of MIM-SPR structures can be tuned by modifying the geometrical properties and have been numerically investigated by using Lumerical’s finite-difference time-domain (FDTD) solutions. The square lattice configuration of 1200 nm to 1400 nm pitch of gold micro-disks of thickness from 80 nm to 120 nm have been conducted. The size of these considered gold patterns, i.e., the diameter of the micro-disks is in the range of 900 nm to 1000 nm. The proposed MIM-SPR structure possessing sensitivity of 370 nm per refractive index unit (RIU), can be applicable for a wide variety of plasmonic sensing, in particular for refractometric biosensors.
{"title":"Near Infrared Metal-insulator-metal Surface Plasmon Resonances for Refractive Index Sensors","authors":"Cam Thi Hong Hoang, T. Ha, V. D. Pham, Q. M. Ngo","doi":"10.15625/0868-3166/16541","DOIUrl":"https://doi.org/10.15625/0868-3166/16541","url":null,"abstract":"This work reports the optical properties of surface plasmon resonance (SPR) based on the metal-insulator-metal (MIM) structure towards a refractive index sensor. The MIM-SPR structure operating near infrared region consists of lateral periodicity of subwavelength gold patterns placed on a stack of thin silica spacer and silver film (acting as a reflector) on a silicon substrate. The reflection spectra and the electric field distributions of MIM-SPR structures can be tuned by modifying the geometrical properties and have been numerically investigated by using Lumerical’s finite-difference time-domain (FDTD) solutions. The square lattice configuration of 1200 nm to 1400 nm pitch of gold micro-disks of thickness from 80 nm to 120 nm have been conducted. The size of these considered gold patterns, i.e., the diameter of the micro-disks is in the range of 900 nm to 1000 nm. The proposed MIM-SPR structure possessing sensitivity of 370 nm per refractive index unit (RIU), can be applicable for a wide variety of plasmonic sensing, in particular for refractometric biosensors.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89734823","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 : 2022-03-27DOI: 10.15625/0868-3166/16124
Nguyen Thi Xuan Huynh, V. Chihaia, D. Son
Graphene is a promising candidate for CO2 capture and storage. Doping graphene with other elements is an effective way to modify its CO2 storage ability. The literature has shown that the N and B doping could change the adsorption strength of CO2 on the graphene substrate. However, there is no research available to elucidate the adsorption sites and the physical properties underlying the interaction of CO2 with the N and B doped systems. Therefore, this paper is devoted to clarifying the current topic using the self-consistent van der Waals density functional theory calculations. The results showed that the N and B doping increases and decreases the adsorption energy of CO2, respectively. The reason is that there are more peaks of the electronic density of states of CO2 participating in the interaction with the N p orbital than with the B p orbital.
{"title":"Insights into Interaction of CO(_2) with N and B-doped Graphenes","authors":"Nguyen Thi Xuan Huynh, V. Chihaia, D. Son","doi":"10.15625/0868-3166/16124","DOIUrl":"https://doi.org/10.15625/0868-3166/16124","url":null,"abstract":"Graphene is a promising candidate for CO2 capture and storage. Doping graphene with other elements is an effective way to modify its CO2 storage ability. The literature has shown that the N and B doping could change the adsorption strength of CO2 on the graphene substrate. However, there is no research available to elucidate the adsorption sites and the physical properties underlying the interaction of CO2 with the N and B doped systems. Therefore, this paper is devoted to clarifying the current topic using the self-consistent van der Waals density functional theory calculations. The results showed that the N and B doping increases and decreases the adsorption energy of CO2, respectively. The reason is that there are more peaks of the electronic density of states of CO2 participating in the interaction with the N p orbital than with the B p orbital.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"13 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88724870","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 : 2022-03-27DOI: 10.15625/0868-3166/16113
Cao Dao Tran, Ngan Luong Truc Quynh, Tuan Anh Cao, Minh Kieu Ngoc
Surface Enhanced Raman Scattering (SERS) is a technique that is increasingly being used to detect trace amounts of various types of molecules, especially organic and biological molecules. The SERS effect is available mainly due to the SERS substrate - a noble metal surface that is rough at the nano level or a set of noble metal nanoparticles in a certain arrangement. Such a SERS substrate acts as an analyte Raman signal amplifier and can provide amplification up to millions of times and even more. The amplification coefficient of the SERS substrate is determined mainly by the number of ‘hot spots’ it contains as well as the ‘hotness’ of these spots. In turn, a ‘hot spot’ is a certain space around the tips or a nanogap between particles, where the local electromagnetic field is intensely enhanced, while the ‘hotness’ is determined by the sharpness of the tips (the sharper the hotter) and tightness of the gaps (the narrower the hotter). This report presents an overview of the research results of fabricating a type of SERS substrate with a high enhancement factor, which is the SERS substrate made from silver nanostructures coated on the silicon surface. With the aim of increasing the number of ‘hot spots’ and their quality, as well as ensuring uniformity and reproducibility of the SERS substrate, silver nanostructures have been fabricated in various forms, such as nanoparticles, nanodendrites and nanoflowers. In addition, the report also mentions the use of the above silver nanostructures as SERS substrates to detect trace amounts of some pesticides and other toxic agents such as paraquat, pyridaben, thiram, cyanide...
{"title":"Fabrication of Silver Nanostructures in the Form of Particles, Dendrites and Flowers on Silicon for Use in SERS Substrates","authors":"Cao Dao Tran, Ngan Luong Truc Quynh, Tuan Anh Cao, Minh Kieu Ngoc","doi":"10.15625/0868-3166/16113","DOIUrl":"https://doi.org/10.15625/0868-3166/16113","url":null,"abstract":"Surface Enhanced Raman Scattering (SERS) is a technique that is increasingly being used to detect trace amounts of various types of molecules, especially organic and biological molecules. The SERS effect is available mainly due to the SERS substrate - a noble metal surface that is rough at the nano level or a set of noble metal nanoparticles in a certain arrangement. Such a SERS substrate acts as an analyte Raman signal amplifier and can provide amplification up to millions of times and even more. The amplification coefficient of the SERS substrate is determined mainly by the number of ‘hot spots’ it contains as well as the ‘hotness’ of these spots. In turn, a ‘hot spot’ is a certain space around the tips or a nanogap between particles, where the local electromagnetic field is intensely enhanced, while the ‘hotness’ is determined by the sharpness of the tips (the sharper the hotter) and tightness of the gaps (the narrower the hotter). This report presents an overview of the research results of fabricating a type of SERS substrate with a high enhancement factor, which is the SERS substrate made from silver nanostructures coated on the silicon surface. With the aim of increasing the number of ‘hot spots’ and their quality, as well as ensuring uniformity and reproducibility of the SERS substrate, silver nanostructures have been fabricated in various forms, such as nanoparticles, nanodendrites and nanoflowers. In addition, the report also mentions the use of the above silver nanostructures as SERS substrates to detect trace amounts of some pesticides and other toxic agents such as paraquat, pyridaben, thiram, cyanide...","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"169 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77857525","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 : 2022-03-27DOI: 10.15625/0868-3166/16788
N. Ngoc, Nguyen Thi Hien, D. Ha, B. Tung, Bui Xuan Son Hai, V. Lam, Bui Xuan Khuyen
Based on rectangle-shaped structures, we create a dual-band metamaterial perfect absorber (DMPA) in the optical region. The independent-polarization absorption is a significant advantage as well as the simple integrated progress for constituent materials. In particular, absorption can be obtained to be over 90% in a bandwidth of 140 THz (from 608 THz to 748 THz), which is still remained well in the oblique incident angles for the TE-polarization. Our results can be regarded as the groundwork for the near future applications such as photodetectors, energy converters and more.
{"title":"A Rectangle-quartet Metamaterial for Dual-band Perfect Absorption in the Visible Region","authors":"N. Ngoc, Nguyen Thi Hien, D. Ha, B. Tung, Bui Xuan Son Hai, V. Lam, Bui Xuan Khuyen","doi":"10.15625/0868-3166/16788","DOIUrl":"https://doi.org/10.15625/0868-3166/16788","url":null,"abstract":"Based on rectangle-shaped structures, we create a dual-band metamaterial perfect absorber (DMPA) in the optical region. The independent-polarization absorption is a significant advantage as well as the simple integrated progress for constituent materials. In particular, absorption can be obtained to be over 90% in a bandwidth of 140 THz (from 608 THz to 748 THz), which is still remained well in the oblique incident angles for the TE-polarization. Our results can be regarded as the groundwork for the near future applications such as photodetectors, energy converters and more.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"170 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76253352","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 : 2022-03-27DOI: 10.15625/0868-3166/16763
Nguyen Huy Viet, M. Nguyen
We present a theoretical study of electron transport properties through experimentally controllable graphene nanobubbles [P. Jia et al., Nat. Commun. 10 (2019) 1] employing a tight-binding model and the non-equilibrium Green's function formalism. Sharp conductance peaks are observed at low energy region which signifies the emergence of quasi-bound states caused by pseudomagnetic field in the strained nanobubbles. Analysis based on local density of states reveals the nature of electron transmission at peak energies. Our results also show that the emergence of quasi-bound states and its role in electron transport depend on both strain strength and bubble size: when the strain or size of the bubble increases, more quasi-bound states emerge and resonant tunnelling assisted by these quasi-bound states becomes dominant.
本文提出了通过实验可控石墨烯纳米泡进行电子传输特性的理论研究[P]。Jia et al.， Nat comm . 10(2019) 1]采用紧约束模型和非均衡Green函数形式。在低能区观察到尖锐的电导峰，这表明在应变的纳米气泡中出现了由伪磁场引起的准束缚态。基于局域态密度的分析揭示了电子在峰值能量下传输的本质。我们的研究结果还表明，准束缚态的出现及其在电子输运中的作用取决于应变强度和气泡尺寸:当气泡的应变或尺寸增加时，更多的准束缚态出现，这些准束缚态辅助的共振隧穿成为主导。
{"title":"Electron Transport Through Experimentally Controllable Parabolic Bubbles on Graphene Nanoribbons","authors":"Nguyen Huy Viet, M. Nguyen","doi":"10.15625/0868-3166/16763","DOIUrl":"https://doi.org/10.15625/0868-3166/16763","url":null,"abstract":"We present a theoretical study of electron transport properties through experimentally controllable graphene nanobubbles [P. Jia et al., Nat. Commun. 10 (2019) 1] employing a tight-binding model and the non-equilibrium Green's function formalism. Sharp conductance peaks are observed at low energy region which signifies the emergence of quasi-bound states caused by pseudomagnetic field in the strained nanobubbles. Analysis based on local density of states reveals the nature of electron transmission at peak energies. Our results also show that the emergence of quasi-bound states and its role in electron transport depend on both strain strength and bubble size: when the strain or size of the bubble increases, more quasi-bound states emerge and resonant tunnelling assisted by these quasi-bound states becomes dominant.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74209057","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 : 2022-03-27DOI: 10.15625/0868-3166/16457
Hoat Do Minh, Jonathan Guerrero Sanchez, R. Perez, J.F. Rivas Silva, G. Cocoletzi
In this work, the structural, electronic, and magnetic properties of the Sr(_{1-x})Mn(_{x})F(_{2}) (x = 0, 0.25, 0.5, 0.75, and 1) compounds are investigated using first-principles calculations. Crystallizing in fluorite structure, SrF(_{2}) is a magnetism-free indirect gap insulator with band gap of 11.61 eV as determined by the reliable mBJK functional. Mn substitution induces the magnetic insulator behavior as both spin configurations exhibit large band gaps with a strong spin-polarization. Specifically, spin-up energy gaps of 8.554, 7.605, 6.902, and 6.154 eV are obtained for Sr(_{0.75})Mn(_{0.25})F(_{2}), Sr(_{0.5})Mn(_{0.5})F(_{2}), Sr(_{0.25})Mn(_{0.75})F(_{2}), and MnF(_{2}), respectively. Whereas, the spin-down state shows larger values of 8.569, 8.864, 9.307, and 9.837 eV, respectively. Consequently, significant magnetization is induced and an integer total spin magnetic moment of 5 (mu_{B}) is obtained, being produced mainly by the spin-up Mn-3d state. Finally, the formation enthalpy and cohesive energy are determined, which indicate good thermodynamic and structural stability of the studied materials. Results suggest that Mn substitution at the Sr-sites of SrF(_{2}) compound may be an efficient approach to create new magnetic materials to be used in the spintronic devices.
在这项工作中，使用第一性原理计算研究了Sr (_{1-x}) Mn (_{x}) F (_{2}) (x = 0, 0.25, 0.5, 0.75和1)化合物的结构，电子和磁性能。SrF (_{2})结晶为萤石结构，是一种无磁性的间接间隙绝缘体，通过可靠的mBJK函数确定其带隙为11.61 eV。由于两种自旋构型都具有较大的带隙和强的自旋极化，锰取代诱导了磁绝缘体的行为。其中，Sr (_{0.75}) Mn (_{0.25}) F (_{2})、Sr (_{0.5}) Mn (_{0.5}) F (_{2})、Sr (_{0.25}) Mn (_{0.75}) F (_{2})和MnF (_{2})的自旋能隙分别为8.554、7.605、6.902和6.154 eV。而自旋下降态的值较大，分别为8.569、8.864、9.307和9.837 eV。因此，产生了显著的磁化，得到了一个整数的总自旋磁矩为5 (mu_{B})，主要是由自旋向上的Mn-3d态产生的。最后测定了生成焓和结合能，表明所研究材料具有良好的热力学稳定性和结构稳定性。结果表明，在SrF (_{2})化合物的sr位上进行Mn取代可能是制备用于自旋电子器件的新型磁性材料的一种有效方法。
{"title":"Structural, Electronic, and Magnetic Properties of Sr(_{1-x})Mn(_{x})F(_{2}) Alloys Studied by First-principles Calculations","authors":"Hoat Do Minh, Jonathan Guerrero Sanchez, R. Perez, J.F. Rivas Silva, G. Cocoletzi","doi":"10.15625/0868-3166/16457","DOIUrl":"https://doi.org/10.15625/0868-3166/16457","url":null,"abstract":"In this work, the structural, electronic, and magnetic properties of the Sr(_{1-x})Mn(_{x})F(_{2}) (x = 0, 0.25, 0.5, 0.75, and 1) compounds are investigated using first-principles calculations. Crystallizing in fluorite structure, SrF(_{2}) is a magnetism-free indirect gap insulator with band gap of 11.61 eV as determined by the reliable mBJK functional. Mn substitution induces the magnetic insulator behavior as both spin configurations exhibit large band gaps with a strong spin-polarization. Specifically, spin-up energy gaps of 8.554, 7.605, 6.902, and 6.154 eV are obtained for Sr(_{0.75})Mn(_{0.25})F(_{2}), Sr(_{0.5})Mn(_{0.5})F(_{2}), Sr(_{0.25})Mn(_{0.75})F(_{2}), and MnF(_{2}), respectively. Whereas, the spin-down state shows larger values of 8.569, 8.864, 9.307, and 9.837 eV, respectively. Consequently, significant magnetization is induced and an integer total spin magnetic moment of 5 (mu_{B}) is obtained, being produced mainly by the spin-up Mn-3d state. Finally, the formation enthalpy and cohesive energy are determined, which indicate good thermodynamic and structural stability of the studied materials. Results suggest that Mn substitution at the Sr-sites of SrF(_{2}) compound may be an efficient approach to create new magnetic materials to be used in the spintronic devices.","PeriodicalId":10571,"journal":{"name":"Communications in Physics","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88594193","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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