Effect of rotation on the elastic moduli of solid He4
Effect of rotation on the elastic moduli of solid He4
复制标题
旋转对固体He4弹性模量的影响
DOI：
10.1103/physrevb.97.054516
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发表时间：
2018
影响因子：
3.7
通讯作者：
Shirahama K.
中科院分区：
文献类型：
--
作者：
Tsuiki T.;Takahashi D.;Murakawa S.;Okuda Y.;Kono K.;Shirahama K.
我们报告的弹性模量hcp soliddown到15 mK时，样品单向旋转的测量。最近的研究表明，位错的滑移和杂质对位错的钉扎控制着孤子的弹性行为，杂质在固体中的运动类似于布洛赫波。受扭振子研究的最新争议的启发，我们已经进行了直接测量的剪切和杨氏模量的环形solidusing对四分之一圆形状的压电换能器（PZT），而整个装置旋转角速度高达4 rad/s。我们发现，当PZT施加的剪切应变超过一个临界值时，剪切模量在80 mK以下受到旋转的抑制，高于该临界值时，剪切模量降低，因为剪切应变使位错从杂质中脱离出来。对于压力为3.6（5.4）MPa的固体样品，旋转引起的atrad/s的衰减约占总温度变化的14.7（12.3）%。这种减小表明位错钉扎几率降低了几个数量级。我们认为，由于科氏力的作用，自旋下的光子运动变得各向异性，从而减少了平行于旋转轴的位错线。
We report measurements of elastic moduli of hcp soliddown to 15 mK when the samples are rotated unidirectionally. Recent investigations have revealed that the elastic behavior of solidis dominated by gliding of dislocations and pinning of them byimpurities, which move in the solidlike Bloch waves (impuritons). Motivated by the recent controversy of torsional oscillator studies, we have performed direct measurements of shear and Young's moduli of annular solidusing pairs of quarter-circle-shape piezoelectric transducers (PZTs) while the whole apparatus is rotated with angular velocityup to 4 rad/s. We have found that shear modulusis suppressed by rotation below 80 mK, when shear strain applied by PZT exceeds a critical value, above whichdecreases because the shear strain unbinds dislocations fromimpurities. The rotation-induced decrement ofatrad/s is about 14.7(12.3)% of the total change of temperature dependentfor solid samples of pressure 3.6(5.4) MPa. The decrements indicate that the probability of pinning ofon dislocation segmentdecreases by several orders of magnitude. We propose that the motion ofimpuritons under rotation becomes strongly anisotropic by the Coriolis force, resulting a decrease infor dislocation lines aligning parallel to the rotation axis.