RIKEN Center for Emergent Matter Science (CEMS), Wako, Saitama 351-0198, Japan.
National Research Center "Kurchatov Institute", 123182 Moscow, Russia.
Phys Rev Lett. 2019 Aug 16;123(7):076601. doi: 10.1103/PhysRevLett.123.076601.
In a number of physical situations, from polarons to Dirac liquids and to non-Fermi liquids, one encounters the "beyond quasiparticles" regime, in which the inelastic scattering rate exceeds the thermal energy of quasiparticles. Transport in this regime cannot be described by the kinetic equation. We employ the diagrammatic Monte Carlo method to study the mobility of a Fröhlich polaron in this regime and discover a number of nonperturbative effects: a strong violation of the Mott-Ioffe-Regel criterion at intermediate and strong couplings, a mobility minimum at T∼Ω in the strong-coupling limit (Ω is the optical mode frequency), a substantial delay in the onset of an exponential dependence of the mobility for T<Ω at intermediate coupling, and complete smearing of the Drude peak at strong coupling. These effects should be taken into account when interpreting mobility data in materials with strong electron-phonon coupling.
在许多物理情况下，从极化子到狄拉克液体和非费米液体，都会遇到“超越准粒子”的区域，其中非弹性散射率超过准粒子的热能。在这个区域中，输运不能用动力学方程来描述。我们采用图论蒙特卡罗方法来研究这个区域中弗罗利希极化子的迁移率，并发现了一些非微扰效应：在中等和强耦合时，强烈违反莫特-伊奥夫规则准则；在强耦合极限下（Ω是光学模式频率），T∼Ω时迁移率最小；在中等耦合时，迁移率对 T<Ω 的指数依赖性开始时的延迟很大；在强耦合时，完全抹平了德劳德峰。在具有强电子-声子耦合的材料中解释迁移率数据时，应该考虑到这些效应。
