Physica B-condensed Matter最新文献

{"title":"Impurity affected transport properties of quantum well heterostructures with electronic and high-κ dielectric quantum screening","authors":"","doi":"10.1016/j.physb.2024.416535","DOIUrl":"10.1016/j.physb.2024.416535","url":null,"abstract":"<div><p>The effect of electronic and high-κ dielectric quantum screening (<em>ES</em> and <em>DS</em>) on the impurity-limited electron transport properties of <em>quantum well/high-κ dielectric barrier</em> type heterostructures with two-dimensional electron gas (<em>2DEG</em>) is studied theoretically. Characteristic of these heterosystems the <em>2D</em> compound forms of screened impurity potential are employed for the first time. In the framework of <em>2D</em> Debye-Hückel potential form an electron momentum relaxation time (<span><math><mrow><mi>τ</mi></mrow></math></span>) expression depending on the impurity <em>2D</em> screening radius is obtained analytically. A numerical analysis of <span><math><mrow><mi>τ</mi></mrow></math></span> is carried out for the realistic <em>HfO/InSb/HfO</em>_<em>2</em> <em>QW</em> heterostructure taking account both the finite mismatch of the energy bands at the heterointerface and the energy band non-parabolicity of <em>InSb</em>. The contributions of screened potential compound <em>2D</em> forms to <span><math><mrow><mi>τ</mi></mrow></math></span> are established depending on <em>QW</em> width. A significant suppression of the scattering rate <span><math><mrow><msup><mi>τ</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span> (by an order of magnitude) is received with accounting of <em>ES</em> + <em>DS</em> combined effect.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142239654","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of grain boundary and alloy scattering within the Callaway model to calculate lattice thermal conductivity in GaN/AlN superlattice","authors":"","doi":"10.1016/j.physb.2024.416530","DOIUrl":"10.1016/j.physb.2024.416530","url":null,"abstract":"<div><p>The grain boundary and alloy scattering within the Debye-Callaway model were introduced to calculate the temperature-dependent lattice thermal conductivity (LTC) in the GaN/AlN superlattice. The superlattice layers are assumed to be grains, and the sample is then treated as a multigrain material. The computations include various physical parameters related to Aluminum alloy compositions, such as Debye temperature, atomic mass, lattice volume, density, alloy scattering factor and deformation energy. In general, the sample size effect on LTC in this superlattice structure was similar to any single component solids, but it has a significant influence from the grain boundaries represented by the thickness of layers in the form of <span><math><mrow><msub><mrow><mi>L</mi><mi>T</mi><mi>C</mi></mrow><mrow><mi>P</mi><mi>e</mi><mi>a</mi><mi>k</mi><mspace></mspace><mi>p</mi><mi>o</mi><mi>i</mi><mi>n</mi><mi>t</mi><mo>.</mo></mrow></msub><mo>=</mo><mn>5.9925</mn><msup><mi>e</mi><mrow><mn>0.0005</mn><msup><mi>L</mi><mn>2</mn></msup></mrow></msup></mrow></math></span> at the peak point maximum and <span><math><mrow><mi>L</mi><mi>T</mi><mi>C</mi><mrow><mo>(</mo><mrow><mn>600</mn><mi>K</mi></mrow><mo>)</mo></mrow><mo>=</mo><mn>0.344</mn><mi>L</mi></mrow></math></span> at 600K, <span><math><mrow><mi>L</mi></mrow></math></span> is the sample size. The dislocations in these samples are controlled by the inbuilt AlN layers with the dependence of <span><math><mrow><msub><mi>N</mi><mrow><mi>D</mi><mi>i</mi><mi>s</mi><mi>l</mi><mo>.</mo></mrow></msub><mo>=</mo><mo>−</mo><mn>0.542</mn><msub><mi>L</mi><mrow><mi>A</mi><mi>l</mi><mi>N</mi></mrow></msub><mo>+</mo><mn>7.4</mn></mrow></math></span>.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142173257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Narrow-band absorption enhancement and modulation of single layer graphene by surface plasmon polaritons in near-infrared region","authors":"","doi":"10.1016/j.physb.2024.416521","DOIUrl":"10.1016/j.physb.2024.416521","url":null,"abstract":"<div><p>We theoretically study the very sharp absorption enhancement of the single layer graphene by the surface plasmon polaritons in near-infrared region. We place the single layer graphene on the silver substrate surface with a periodic slit array. Such a structure design is helpful to reduce the difficulty in experimental fabrication. By changing the slit period, we can largely tune the absorption peak of the single layer graphene in the wavelength range from 1000 nm to 2000 nm, covering the well-known communication wavelength of 1550 nm. The absorption efficiency of the single layer graphene varies between about 20 % and 80 %, and the absorption bandwidth is reduced from about 10 nm to 1 nm. Moreover, by changing the Fermi energy of the single layer graphene, we can also completely modulate the absorption peak from a maximum to almost zero and thus realize a nearly 100 % modulation depth. This work has a potential application in electro-optic modulators.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142161900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel microwave dielectric ceramic CaB2O4 with low dielectric constant","authors":"","doi":"10.1016/j.physb.2024.416526","DOIUrl":"10.1016/j.physb.2024.416526","url":null,"abstract":"<div><p>A novel microwave dielectric ceramic CaB₂O₄ with low dielectric constant was synthesized by the solid-state reaction method. The impact of diverse Ca/B ratios on the phase composition, microstructure and dielectric properties of CaB_2+xO_4+3x/2 (x = 0–0.6) ceramics was investigated. The bond ionicity and the lattice energy of CaB_2+xO_4+3x/2 ceramics were calculated by the P-V-L theory. The appropriate excess of boron facilitated the densification of CaB₂O₄ ceramics, resulting in the stable crystal structure and enhanced dielectric properties. CaB_2.3O_4.45 ceramic sintered at 950 °C had excellent properties: <em>ε</em>_<em>r</em> = 6.03, <em>Q×f</em> = 37,962 GHz, and <em>τ</em>_<em>f</em> = −24.7 ppm/°C. The influence of TiO₂ on the microwave dielectric properties of CaB₂O₄ was investigated, 87 wt% CaB₂O₄ - 13 wt% TiO₂ ceramics sintered at 950 °C showed a zero <em>τ</em>_<em>f</em> value.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240465","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cu2Se/MXene (Ti3C2Tx) composite achieved ultra-low thermal conductivity and enhanced thermoelectric performance","authors":"","doi":"10.1016/j.physb.2024.416528","DOIUrl":"10.1016/j.physb.2024.416528","url":null,"abstract":"<div><p>Due to the significant mismatch in phonon density of states between carbon (C) and Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se, the thermal conductivity of Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se can be notably enhanced by incorporating low-dimensional carbon-based materials. This study propose an innovative approach where two-dimensional MXene material Ti<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>T<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> is introduced into Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se, creating numerous Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se/MXene heterogeneous interfaces within the matrix. These interfaces induce high-density dislocations, which enhance multi-scale phonon scattering efficiency. Consequently, they significantly reduce lattice thermal conductivity across the entire temperature range tested. Additionally, the heterogeneous interfaces facilitate energy filtration, selectively filtering out low-energy carriers and thereby optimizing the high intrinsic carrier concentration of Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se to a certain extent. Finally, the total thermal conductivity of the Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se/0.4 wt% Ti<span><math><msub><mrow></mrow><mrow><mn>3</mn></mrow></msub></math></span>C<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>T<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> sample at 795 K is markedly lower at 0.27 Wm⁻¹K⁻¹ compared to the average level of Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se materials. As a result, the <span><math><mrow><mi>Z</mi><msub><mrow><mi>T</mi></mrow><mrow><mi>m</mi><mi>a</mi><mi>x</mi></mrow></msub></mrow></math></span> reaches 2.11, reflecting a 109% enhancement compared to pristine Cu<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span>Se.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnetic properties of binary alloys Ni1−xMox and Ni1−yCuy close to critical concentrations","authors":"","doi":"10.1016/j.physb.2024.416524","DOIUrl":"10.1016/j.physb.2024.416524","url":null,"abstract":"<div><p>The search for the ferromagnetic quantum critical point (FM QCP) has always been a captivating research topic in the scientific community. In pursuit of this goal, we introduced nonmagnetic transition metals to alloy with elemental nickel, and studied the magnetic properties of nickel binary alloys Ni<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>x</mi></mrow></msub></math></span>Mo<span><math><msub><mrow></mrow><mrow><mi>x</mi></mrow></msub></math></span> and Ni<span><math><msub><mrow></mrow><mrow><mn>1</mn><mo>−</mo><mi>y</mi></mrow></msub></math></span>Cu<span><math><msub><mrow></mrow><mrow><mi>y</mi></mrow></msub></math></span> as a function of <span><math><mi>x</mi></math></span> and <span><math><mi>y</mi></math></span> up to the critical concentrations <span><math><msub><mrow><mi>x</mi></mrow><mrow><mi>c</mi><mi>r</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>y</mi></mrow><mrow><mi>c</mi><mi>r</mi></mrow></msub></math></span> at which the FM transition <span><math><msub><mrow><mi>T</mi></mrow><mrow><mi>C</mi></mrow></msub></math></span> disappears. <span><math><mrow><msub><mrow><mi>T</mi></mrow><mrow><mi>C</mi></mrow></msub><mo>−</mo><mi>x</mi><mrow><mo>(</mo><mi>y</mi><mo>)</mo></mrow></mrow></math></span> phase diagrams were constructed via the Arrott–Noakes scaling of magnetization data. An enhanced Sommerfeld coefficient (the value of <span><math><mrow><mi>C</mi><mo>/</mo><mi>T</mi></mrow></math></span> as <span><math><mrow><mi>T</mi><mo>→</mo><mn>0</mn></mrow></math></span>) is observed near <span><math><msub><mrow><mi>x</mi></mrow><mrow><mi>c</mi><mi>r</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>y</mi></mrow><mrow><mi>c</mi><mi>r</mi></mrow></msub></math></span>, manifesting the effect of quantum fluctuations. However, the spin glass behavior is identified through the ac magnetic susceptibility measurements. This observation rules out the possibility of the existence of the FM QCP in both systems.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142230623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Sr doping on the structural and magnetic properties of (Y,Gd)Ba1−xSrxCuFeO5 (x=0,0.25,0.5) studied by FTIR and 57Fe Mössbauer spectroscopy","authors":"","doi":"10.1016/j.physb.2024.416523","DOIUrl":"10.1016/j.physb.2024.416523","url":null,"abstract":"<div><p>The effect of replacing Y by Gd and Ba by Sr is studied by Fourier Transform Infrared spectroscopy, ⁵⁷Fe Mössbauer spectroscopy and DC susceptibility measurements. Site disorder is inferred from FTIR and Mössbauer spectra using a Maximum-Entropy-Method. A doping dependence of the IR peaks and the hyperfine parameters is explained in terms of bonding energies and electric field gradient variations in the crystal lattice caused by Fe/Cu site disorder. We find an influence of doping on the structural and magnetic properties through a correlation of hyperfine parameters such as the electric quadrupole splitting and the magnetic hyperfine field. We also find that a paramagnetic volume fraction appears for GdBaCuFeO<span><math><msub><mrow></mrow><mrow><mn>5</mn></mrow></msub></math></span> that increases upon Sr doping at the Ba site. The different behavior of the susceptibility upon replacing Y by Gd is attributed to the lack of a favorable environment to enable a Gd-Fe or Gd-Cu exchange interaction.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal and thermodynamic properties of Tb2Ni2X, (X = Al, Ga)","authors":"","doi":"10.1016/j.physb.2024.416525","DOIUrl":"10.1016/j.physb.2024.416525","url":null,"abstract":"&lt;div&gt;&lt;p&gt;The crystal and thermodynamic properties of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;Tb&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;Ni&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mtext&gt;X&lt;/mtext&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (X = Al, Ga) are reported through measurements of X-ray diffraction (XRD), magnetic susceptibility, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;, magnetization, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;M&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;μ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;0&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mi&gt;H&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; and heat capacity, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. XRD pattern analysis confirms the orthorhombic &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;W&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;CoB&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;-type structure with the space group of &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;I&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;mi&gt;m&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;. &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; at high temperature for both compounds follows the Curie – Weiss relationship giving an effective magnetic moment close to that expected for the trivalent Tb ion. The low-temperature &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mi&gt;χ&lt;/mi&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; data indicate that both compounds order antiferromagnetically at &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;N&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; = 41 K (40.4 K) and 41.5 K (41.4 K) for Al and Ga compounds, respectively. &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;p&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; data of the nonmagnetic counterparts &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;Y&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mtext&gt;Ni&lt;/mtext&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;2&lt;/mn&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mtext&gt;X&lt;/mtext&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; (X = Al, Ga) are well described by the Debye model giving a Debye temperature, &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;θ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;D&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; = 236.9(4) K and 225.3(2) K for Al and Ga compounds, respectively. The low-temperature part of the &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt;-magnetic contribution to the total heat capacity, &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;C&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;mrow&gt;&lt;mo&gt;(&lt;/mo&gt;&lt;mi&gt;T&lt;/mi&gt;&lt;mo&gt;)&lt;/mo&gt;&lt;/mrow&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; can be described by the antiferromagnetic spin-wave dispersion, giving an energy gap &lt;span&gt;&lt;math&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;Δ&lt;/mi&gt;&lt;/mrow&gt;&lt;mrow&gt;&lt;mi&gt;s&lt;/mi&gt;&lt;mi&gt;w&lt;/mi&gt;&lt;/mrow&gt;&lt;/msub&gt;&lt;/math&gt;&lt;/span&gt; = 47(3) K and 26(2) K for Al and Ga compounds, respectively. The &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;mn&gt;4&lt;/mn&gt;&lt;mi&gt;f&lt;/mi&gt;&lt;/mrow&gt;&lt;/math&gt;&lt;/span&gt; – magnetic entropy &lt;span&gt;&lt;math&gt;&lt;mrow&gt;&lt;msub&gt;&lt;mrow&gt;&lt;mi&gt;S&lt;/","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142167902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of methylammonium tin iodide thin films prepared by sequential physical vapour deposition","authors":"","doi":"10.1016/j.physb.2024.416496","DOIUrl":"10.1016/j.physb.2024.416496","url":null,"abstract":"<div><p>Methylammonium tin triiodide (MASnI₃) films were grown through Sequential Physical Vapour Deposition (SPVD) without breaking the vacuum and optimized by varying MAI thickness and annealing time while keeping SnI₂ thickness constant. The film's crystallinity increased with MAI thickness and annealing time. Optimal bandgap was attained for the film with 500 nm MAI annealed for 20 &amp; 40 min. FE-SEM revealed densely packed, large grains, increasing in size with MAI thickness and on annealing from 0 to 40 min and decreasing at 80 min. The film with 300 nm MAI thickness annealed for 40 min showed the strongest PL intensity suggesting reduced carrier recombination losses. Trap densities reduced with annealing time and MAI thickness due to improvements in films' crystallinity, grain sizes and reduced grain boundaries which act as carrier trapping sites. Hence, films prepared through SPVD, exhibit excellent structural, optical, and morphological properties, suitable for photovoltaic applications.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First-principles study of mechanical, electronic structure, optical, thermodynamic properties and hydrogen storage for new hydride perovskites XInH3 (X=Rb, Cs)*","authors":"","doi":"10.1016/j.physb.2024.416488","DOIUrl":"10.1016/j.physb.2024.416488","url":null,"abstract":"<div><p>The structure, mechanical, electronic, optical, thermodynamic properties and hydrogen storage capacities of XInH₃ (X = Rb, Cs) are simulated using the first-principles method. The calculated mechanical properties demonstrate that XInH₃ compounds own anisotropy, mechanical stability, and ductility. XInH₃'s interatomic bonds are ionic and bond stretching predominates in XInH₃ in accordance with Kleinman's parameter. The greater machinability index of RbInH₃ means that it is more suitable for machining. According to the electronic structures, XInH₃ are metallic. Analysis of their optical properties demonstrates that XInH₃ have good absorption properties in the UV range. Moreover, thermodynamic properties, including free energy, energy, entropy and heat capacity are also analyzed. Taking into account the formation energy, Born stability criterion and phonon dispersion curve, XInH₃ compounds show thermodynamic, mechanical, and dynamic stability. In addition, RbInH₃ and CsInH₃ have gravimetric hydrogen storage capacities with 1.466 and 1.191 wt%, respectively. These results are evidence that XInH₃ hydrides are potential candidate materials in the field of hydrogen storage. These investigations provide an important theoretical basis for further exploring the application of hydride materials in the field of hydrogen storage.</p></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":null,"pages":null},"PeriodicalIF":2.8,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}