Electrons in a metal subject to magnetic field commonly exhibit oscillatory behavior as the field strength varies, with a period set by the area of quantized electronic orbits. Recent experiments on elemental bismuth have revealed oscillations for fields above 9 tesla that do not follow this simple dependence and have been interpreted as a signature of electron fractionalization in the bulk. We argue instead that a simple explanation in terms of the surface states of bismuth exists when additional features of the experiment are included. These surface electrons are known to have significant spin-orbit interaction. We show the observed oscillations are in quantitative agreement with the surface theory, which we propose to test by studying the effect of the Zeeman coupling in higher fields, dependence on the field orientation, and the thickness of the samples.
Strong- to weak-coupling superconductivity in high-$T_c$ bismuthates: revisiting the phase diagram via $μ$SR
在铋酸盐中发现超导电性几十年后，它们的电子-声子耦合强度及其随掺杂的演变仍然令人困惑。为了澄清这些问题，多晶空穴掺杂Ba $_{1-x}$ K $_{x}$ Bi O $_3$（$0.1 \le x \le 0.6$）样品的系统合成和它们的体和微观超导性能的磁化率和μ子自旋旋转/弛豫（$μ$ SR）的装置进行了研究，分别。Ba $_{1-x}$ K $_{x}$ Bi O $_3$的相图可靠地扩展到$x = 0.6$，它仍然被发现是一个大块超导体。晶格参数$a$随K含量线性增加，意味着均匀的化学掺杂。通过横向场（TF）- $μ$ SR测量的低温超流密度表明，零温度间隙$Δ_0/k_\mathrm{B}T_c$ = 2.15，2.10和1.75，磁穿透深度$λ_0$ = 219，184和279 nm（$x$ = 0.3，0.4和0.6）分别为各向同性全带隙超导态。超导带隙的变化，从一个接近理想的BCS值（1.76 $k_\mathrm{B}$ $T_c$在弱耦合的情况下）在过掺杂的$x$ = 0.6的区域，以高得多的值在最佳掺杂的情况下，意味着在掺杂的电子-声子耦合逐渐减少。
Specific features of the magnetic-field dependences of electrical resistivity in Bi--Mn solid solutions with low Mn content
Verkin Institute for Low Temperature Physics and Engineering（维尔金低温物理与工程学院）；W. Trzebiatowski Institute for Low Temperatures & Structure Research PAS（W·特热比亚托夫斯基低温与结构研究研究所（波兰科学院））；Lappeenranta University of Technology, School of Engineering Science（拉彭兰塔理工大学工程学院）
Phase transitions in multiferroic BiFeO3 crystals, thin-layers, and ceramics: Enduring potential for a single phase, room-temperature magnetoelectric 'holy grail'
