Heath Joshuah T, Bedell Kevin S
Physics Department, Boston College, Chestnut Hill, Massachusetts 02467, United States of America.
J Phys Condens Matter. 2020 Sep 8;32(48). doi: 10.1088/1361-648X/abaeb0.
Motivated by recent experiments in the Kitaev honeycomb lattice, Kondo insulators, and the 'Luttinger's theorem-violating' Fermi liquid phase of the underdoped cuprates, we extend the theoretical machinery of Landau-Fermi liquid theory to a system of itinerant, interacting Majorana-like particles. Building upon a previously introduced model of 'nearly self-conjugate' fermionic polarons, a Landau-Majorana kinetic equation is introduced to describe the collective modes and Fermi surface instabilities in a fluid of particles whose fermionic degrees of freedom obey the Majorana reality condition. At large screening, we show that the Landau-Majorana liquid harbors a Lifshitz transition for specific values of the driving frequency. Moreover, we find the dispersion of the zero sound collective mode in such a system, showing that there exists a specific limit where the Landau-Majorana liquid harbors a stability against Pomeranchuk deformations unseen in the conventional Landau-Fermi liquid. With these results, our work paves the way for possible extensions of the Landau quasiparticle paradigm to nontrivial metallic phases of matter.
受近期在Kitaev蜂窝晶格、近藤绝缘体以及欠掺杂铜酸盐中违反“卢廷格定理”的费米液体相实验的启发，我们将朗道费米液体理论的理论框架扩展到一个巡游的、相互作用的类马约拉纳粒子系统。基于先前引入的“近乎自共轭”费米子极化子模型，引入了一个朗道 - 马约拉纳动力学方程，以描述其费米子自由度满足马约拉纳实性条件的粒子流体中的集体模式和费米面不稳定性。在大屏蔽情况下，我们表明，对于特定的驱动频率值，朗道 - 马约拉纳液体存在一个里夫希茨转变。此外，我们找到了这种系统中零声集体模式的色散关系，表明存在一个特定极限，在该极限下朗道 - 马约拉纳液体对常规朗道费米液体中未出现的波梅兰丘克形变具有稳定性。基于这些结果，我们的工作为将朗道准粒子范式扩展到非平凡金属物质相开辟了道路。
