{"title":"Elastic and breaking properties of epitaxial face-centered crystals in neutron star crusts and white dwarf cores","authors":"D. A. Baiko","doi":"10.1002/ctpp.202400004","DOIUrl":null,"url":null,"abstract":"<p>Crystallization of dense matter in neutron star crusts and white dwarf cores may be similar to epitaxial crystal growth in terrestrial laboratories. However, in stellar crystals, the spacing between horizontal planes has to gradually increase with the outward movement of the crystallization front, tracing decrease of the electron density. This process produces Coulomb crystals with stretched rather than cubic elementary cells. We extend the analysis of the elastic and breaking properties of such crystals to the face-centered (fc) lattice. Shear deformations orthogonal to the stretch direction have been studied for 22 crystallographic shear planes. A common property for all these planes is the reduction and eventual nulling of the breaking shear strain with deviation from the unstretched configuration. The effective shear moduli for deformations orthogonal to the stretch direction have been calculated. It is possible that the epitaxial crystallization in compact stars results in a formation of large-scale crystallites or, at least, in growth of the whole crystallization front perpendicular to particular crystallographic planes. For fc structure growth orthogonal to the <span></span><math>\n <semantics>\n <mrow>\n <mrow>\n <mo>{</mo>\n <mn>111</mn>\n <mo>}</mo>\n </mrow>\n </mrow>\n <annotation>$$ \\left\\{111\\right\\} $$</annotation>\n </semantics></math> planes, we expect that, at any density, <span></span><math>\n <semantics>\n <mrow>\n <mo>∼</mo>\n <mn>5</mn>\n <mo>%</mo>\n </mrow>\n <annotation>$$ \\sim 5\\% $$</annotation>\n </semantics></math> (<span></span><math>\n <semantics>\n <mrow>\n <mo>∼</mo>\n <mn>0.5</mn>\n <mo>%</mo>\n </mrow>\n <annotation>$$ \\sim 0.5\\% $$</annotation>\n </semantics></math>) of crystallite height is occupied by layers one (two) orders of magnitude weaker than the bulk of the crystallite. This may be important for realistic modeling of crustquakes on neutron stars.</p>","PeriodicalId":10700,"journal":{"name":"Contributions to Plasma Physics","volume":"64 6","pages":""},"PeriodicalIF":1.3000,"publicationDate":"2024-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Contributions to Plasma Physics","FirstCategoryId":"101","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/ctpp.202400004","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, FLUIDS & PLASMAS","Score":null,"Total":0}
引用次数: 0
Abstract
Crystallization of dense matter in neutron star crusts and white dwarf cores may be similar to epitaxial crystal growth in terrestrial laboratories. However, in stellar crystals, the spacing between horizontal planes has to gradually increase with the outward movement of the crystallization front, tracing decrease of the electron density. This process produces Coulomb crystals with stretched rather than cubic elementary cells. We extend the analysis of the elastic and breaking properties of such crystals to the face-centered (fc) lattice. Shear deformations orthogonal to the stretch direction have been studied for 22 crystallographic shear planes. A common property for all these planes is the reduction and eventual nulling of the breaking shear strain with deviation from the unstretched configuration. The effective shear moduli for deformations orthogonal to the stretch direction have been calculated. It is possible that the epitaxial crystallization in compact stars results in a formation of large-scale crystallites or, at least, in growth of the whole crystallization front perpendicular to particular crystallographic planes. For fc structure growth orthogonal to the planes, we expect that, at any density, () of crystallite height is occupied by layers one (two) orders of magnitude weaker than the bulk of the crystallite. This may be important for realistic modeling of crustquakes on neutron stars.
中子星外壳和白矮星内核中致密物质的结晶过程可能类似于地球实验室中的外延晶体生长。然而,在恒星晶体中,水平面之间的间距必须随着结晶前沿的向外移动而逐渐增大,这与电子密度的降低有关。这一过程会产生具有拉伸而非立方基本单元的库仑晶体。我们将这种晶体的弹性和断裂特性分析扩展到面心晶格。我们研究了 22 个晶体学剪切平面与拉伸方向正交的剪切变形。所有这些平面的一个共同特性是,在偏离未拉伸构型时,断裂剪切应变会减小并最终消失。我们计算了与拉伸方向正交的变形的有效剪切模量。致密星的外延结晶可能会形成大尺度晶粒,或者至少整个结晶前沿垂直于特定结晶平面生长。对于正交于平面的 fc 结构生长,我们预计在任何密度下,晶体高度的()都会被比晶体主体弱一(两)个数量级的晶层所占据。这对于中子星上壳震的现实建模可能很重要。