Papers in Physics最新文献_第4页

Theory of terahertz Smith-Purcell radiation from a cylindrical grating 圆柱光栅的太赫兹史密斯-珀塞尔辐射理论

IF 0.9

Papers in Physics Pub Date : 2019-10-08 DOI: 10.4279/pip.110007

Z. Rezaei, B. Farokhi

引用次数: 1

On the impact of the stress situation on the optical properties of $WSe_2$ monolayers under high pressure 高压下应力状态对$WSe_2$单层光学性能的影响

IF 0.9

Papers in Physics Pub Date : 2019-06-21 DOI: 10.4279/PIP.110005

A. Francisco-López, B. Han, D. Lagarde, X. Marie, B. Urbaszek, C. Robert, A. Goñi

{"title":"On the impact of the stress situation on the optical properties of $WSe_2$ monolayers under high pressure","authors":"A. Francisco-López, B. Han, D. Lagarde, X. Marie, B. Urbaszek, C. Robert, A. Goñi","doi":"10.4279/PIP.110005","DOIUrl":"https://doi.org/10.4279/PIP.110005","url":null,"abstract":"We have studied the optical properties of $WSe_2$ monolayers (ML) by means of photoluminescence (PL), PL excitation (PLE) and Raman scattering spectroscopy at room temperature and as a function of hydrostatic pressure up to ca. 12 GPa. For comparison the study comprises two cases: A single $WSe_2$ ML directly transferred onto one of the diamonds of the diamond anvil cell and a $WSe_2$ ML encapsulated into hexagonal boron nitride (hBN) layers. The pressure dependence of the A and B exciton, as determined by PL and PLE, respectively, is very different for the case of the bare $WSe_2$ ML and the $hBN/WSe_2-ML/hBN$ heterostructure. Whereas for the latter the A and B exciton energy increases linearly with increasing pressure at a rate of 3.5 to 3.8 meV/GPa, for the bare $WSe_2$ ML the A and B exciton energy decreases with a coefficient of -3.1 and -1.3 meV/GPa, respectively. We interpret that this behavior is due to a different stress situation. For a single ML the stress tensor is essentially uniaxial with the compressive stress component in the direction perpendicular to the plane of the ML. In contrast, for the substantially thicker $hBN/WSe_2-ML/hBN$ heterostructure the compression is hydrostatic. The results from an analysis of the pressure dependence of the frequency of Raman active modes comply with the interpretation of having a different stress situation in each case. \u0000Reviewed by: A. San Miguel, Institut Lumière Matière, Université de Lyon, France; Edited by: J. S. Reparaz","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44340001","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}

引用次数: 6

Structural correlations in $Cs_2CuCl_4$: Pressure dependence of electronic structures Cs_2CuCl_4$中的结构相关性:电子结构的压力依赖性

IF 0.9

Papers in Physics Pub Date : 2019-06-21 DOI: 10.4279/PIP.110004

E. Jara, J. A. Barreda-Argüeso, Jesús González, R. Valiente, F. Rodríguez

{"title":"Structural correlations in $Cs_2CuCl_4$: Pressure dependence of electronic structures","authors":"E. Jara, J. A. Barreda-Argüeso, Jesús González, R. Valiente, F. Rodríguez","doi":"10.4279/PIP.110004","DOIUrl":"https://doi.org/10.4279/PIP.110004","url":null,"abstract":"We have investigated the crystal structure of $Cs_2CuCl_4$ in the 0-20 GPa range as a function of pressure and how pressure affects its electronic properties by means of optical absorption spectroscopy. In particular, we focused on the electronic properties in the low-pressure Pnma phase, which are mainly related to the tetrahedral $CuCl_4^{2-}$ units distorted by the Jahn-Teller effect. This study provides a complete characterization of the electronic structure of $Cs_2CuCl_4$ in the Pmna phase as a function of the cell volume and the $Cu-Cl$ bond length, $R_{Cu-Cl}$. Interestingly, the opposite shift of the charge-transfer band-gap and the $Cu^{2+}$ d-d crystal-field band shift with pressure are responsible for the strong piezochromism of $Cs_2CuCl_4$. We have also explored the high-pressure structure of $Cs_2CuCl_4$ above 4.9 GPa yielding structural transformations that are probably associated with a change of coordination around $Cu^{2+}$. Since the high-pressure phase appears largely amorphized, any structural information from X-ray diffraction is ruled out. We use electronic probes to get structural information of the high-pressure phase. \u0000Edited by: A. Goñi, A. Cantarero, J. S. Reparaz","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45089747","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}

引用次数: 1

Pressure-induced Lifshitz transition in FeSe$_{0.88}$S$_{0.12}$ probed via $^{77}$Se-NMR 用$^{77}$Se-NMR探测FeSe$_{0.88}$S$ $_{0.12}$的压力诱导Lifshitz跃迁

IF 0.9

Papers in Physics Pub Date : 2019-06-18 DOI: 10.4279/PIP.110003

T. Kuwayama, K. Matsuura, Y. Mizukami, S. Kasahara, Y. Matsuda, T. Shibauchi, Y. Uwatoko, N. Fujiwara

引用次数: 0

Nuclear magnetic resonance on $LaFeAsO_{0.4}H_{0.6}$ at 3.7 GPa 3.7 GPa下$LaFeAsO_{0.4}H_{0.6}$的核磁共振

IF 0.9

Papers in Physics Pub Date : 2019-06-04 DOI: 10.4279/PIP.110002

N. Fujiwara, M. Takeuchi, T. Kuwayama, Shusaku Nakagawa, S. Iimura, S. Matsuishi, H. Hosono

引用次数: 0

Vortex dynamics under pulsatile flow in axisymmetric constricted tubes 轴对称收缩管脉动流下的旋涡动力学

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Papers in Physics Pub Date : 2019-04-23 DOI: 10.4279/pip.120002

N. Barrere, J. Brum, Alexandre L’Her, Gustavo L. Saras'ua, C. Cabeza

{"title":"Vortex dynamics under pulsatile flow in axisymmetric constricted tubes","authors":"N. Barrere, J. Brum, Alexandre L’Her, Gustavo L. Saras'ua, C. Cabeza","doi":"10.4279/pip.120002","DOIUrl":"https://doi.org/10.4279/pip.120002","url":null,"abstract":"Improved understanding of how vortices develop and propagate under pulsatile flow can shed important light on the mixing and transport processes occurring in such systems, including the transition to turbulent regime. For example, the characterization of pulsatile flows in obstructed artery models serves to encourage research into flow-induced phenomena associated with changes in morphology, blood viscosity, wall elasticity and flow rate. In this work, an axisymmetric rigid model was used to study the behaviour of the flow pattern with varying degrees constriction ($d_0$) and mean Reynolds ($bar{Re}$) and Womersley numbers ($alpha$). Velocity fields were obtained experimentally using Digital Particle Image Velocimetry and generated numerically. For the acquisition of data, $bar{Re}$ was varied from 385 to 2044, $d_0$ was 1.0 cm and 1.6 cm, and $alpha$ was varied from 17 to 33 in the experiments and from 24 to 50 in the numerical simulations. Results for the Reynolds number considered showed that the flow pattern consisted of two main structures: a central jet around the tube axis and a recirculation zone adjacent to the inner wall of the tube, where vortices shed. Using the vorticity fields, the trajectory of vortices was tracked and their displacement over their lifetime calculated. The analysis led to a scaling law equation for maximum vortex displacement as a function of a dimensionless variable dependent on the system parameters Re and $alpha$.","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46732104","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}

引用次数: 3

Fluorine chemistry at extreme conditions: possible synthesis of $HgF_4$ 极端条件下的氟化学:$HgF_4$的可能合成

IF 0.9

Papers in Physics Pub Date : 2019-02-27 DOI: 10.4279/PIP.110001

M. Pravica, Sarah N. Schyck, Blake Harris, P. Cifligu, Eunja Kim, B. Billinghurst

{"title":"Fluorine chemistry at extreme conditions: possible synthesis of $HgF_4$","authors":"M. Pravica, Sarah N. Schyck, Blake Harris, P. Cifligu, Eunja Kim, B. Billinghurst","doi":"10.4279/PIP.110001","DOIUrl":"https://doi.org/10.4279/PIP.110001","url":null,"abstract":"By irradiating a pressurized mixture of a fluorine-bearing compound ($XeF_2$) and $HgF_2$ with synchrotron hard x-rays (>7 keV) inside a diamond anvil cell, we have observed dramatic changes in the far-infrared spectrum within the 30-35 GPa pressure range which suggest that we may have formed $HgF_4$ in the following way: $XeF_2 xrightarrow{hv} Xe + F_2$ (photochemically) and $HgF_2 + F_2 rightarrow HgF_4$ (30 GPa < P < 35 GPa). This lends credence to recent theoretical calculations by Botana et al. that suggest that Hg may behave as a transition metal at high pressure in an environment with an excess of molecular fluorine. The spectral changes were observed to be reversible during pressure cycling above and below the above mentioned pressure range until a certain point when we suspect that molecular fluorine diffused out of the sample at lower pressure. Upon pressure release, $HgF_2$ and trace $XeF_2$ were observed to be remaining in the sample chamber suggesting that much of the $Xe$ and $F_2$ diffused and leaked out from the sample chamber. \u0000 \u0000Received: 29 October 2018, Accepted: 18 January 2019; Edited by: A. Goñi, A. Cantarero, J. S. Reparaz; DOI: http://dx.doi.org/10.4279/PIP.110001 \u0000Cite as: M Pravica, S Schyck, B Harris, P Cifligu, E Kim, B Billinghurst, Papers in Physics 11, 110001 (2019). \u0000This paper, by M Pravica, S Schyck, B Harris, P Cifligu, E Kim, B Billinghurst, is licensed under the Creative Commons Attribution License 4.0. \u0000 ","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46485301","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}

引用次数: 3

Development of two-stage multi-anvil apparatus for low-temperature measurements 两级多砧低温测定仪的研制

IF 0.9

Papers in Physics Pub Date : 2019-01-01 DOI: 10.4279/pip.110006

K. Ishigaki, J. Gouchi, S. Nagasaki, J. G. Cheng, Y. Uwatoko

{"title":"Development of two-stage multi-anvil apparatus for low-temperature measurements","authors":"K. Ishigaki, J. Gouchi, S. Nagasaki, J. G. Cheng, Y. Uwatoko","doi":"10.4279/pip.110006","DOIUrl":"https://doi.org/10.4279/pip.110006","url":null,"abstract":"The two-stage 6-8 multi-anvil (MA8) apparatus is an important large-volume, high-pressure technique that has been widely used in the high pressure mineralogy and material synthesis, mainly at room temperature or above. Recently, we have successfully developed a two-stage MA8 apparatus for low-temperature physical property measurements. The first-stage anvils at top and bottom sides are fabricated as a single piece in order to reduce the total size of the cylindrical module, which is put in a top-loading high pressure cryostat and compressed by a 1000 ton hydraulic press. A castable, split octahedral gasket with integrated fin was specifically designed in order to introduce the electrical leads from the inside sample container filled with a liquid pressure transmitting medium. By using tungsten carbide (WC) second-stage cubes with a truncated edge length of 3 mm and an octahedral gasket with an edge length of 6 mm, we have successfully generated pressure over 20 GPa at room temperature. Since the high pressure limit can be pushed to nearly 100 GPa by using the sintered diamond second-stage cubes, our MA8 apparatus has a great potential to expand the current pressure capacity for precise low-temperature measurements with a large sample volume. Edited by: A. Goñi, A. Cantarero, J. S. Reparaz","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71011144","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}

引用次数: 0

Physical pendulum experiment re-investigated with an accelerometer sensor 用加速度计传感器重新研究物理摆实验

IF 0.9

Papers in Physics Pub Date : 2018-11-07 DOI: 10.4279/PIP.100008

C. Dauphin, F. Bouquet

引用次数: 9

Temperature-dependent transport measurements with Arduino 使用Arduino进行温度相关传输测量

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Papers in Physics Pub Date : 2018-09-16 DOI: 10.4279/pip.100007

A. Hilberer, G. Laurent, A. Lorin, A. Partier, J. Bobroff, F. Bouquet, C. Even, J. Fischbach, C. Marrache-Kikuchi, M. Monteverde, B. Pilette, Q. Quay

{"title":"Temperature-dependent transport measurements with Arduino","authors":"A. Hilberer, G. Laurent, A. Lorin, A. Partier, J. Bobroff, F. Bouquet, C. Even, J. Fischbach, C. Marrache-Kikuchi, M. Monteverde, B. Pilette, Q. Quay","doi":"10.4279/pip.100007","DOIUrl":"https://doi.org/10.4279/pip.100007","url":null,"abstract":"The current performances of single-board microcontrollers render them attractive, not only for basic applications, but also for more elaborate projects, amongst which are physics teaching or research. In this article, we show how temperature-dependent transport measurements can be performed by using an Arduino board, from cryogenic temperatures up to room temperature or above. We focus on two of the main issues for this type of experiments: the determination of the sample temperature and the measurement of its resistance. We also detail two student-led experiments: evidencing the magnetocaloric effect in Gadolinium and measuring the resistive transition of a high critical temperature superconductor. Received: 7 July 2018, Accepted: 27 September 2018; Edited by: A. Marti, M. Monteiro; Reviewed by: R. Marotti, Instituto de Fisica, Facultad de Ingenieria - Universidad de la Republica, Uruguay; DOI: http://dx.doi.org/10.4279/PIP.100007 Cite as: A Hilberer, G Laurent, A Lorin, A Partier, J Bobroff, F Bouquet, C Even, J M Fischbach, C A Marrache Kikuchi, M Monteverde, B Pilette, Q Quay, Papers in Physics 10, 100007(2018) This paper, by A Hilberer, G Laurent, A Lorin, A Partier, J Bobroff, F Bouquet, C Even, J M Fischbach, C A Marrache Kikuchi, M Monteverde, B Pilette, Q Quay , is licensed under the Creative Commons Attribution License 4.0 .","PeriodicalId":19791,"journal":{"name":"Papers in Physics","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2018-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49439899","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}

引用次数: 1