Phase Separation in Kitaev Chain

Abstract

Kitaev chain is a one-dimensional spinless fermion model that has $p$-wave superconducting (SC) states and Majorana zero modes at the edge. Usually this model is analyzed by taking only SC order parameter (OP) into account, but the situation significantly changes when OPs other than the SCOP are included. It turns out that the SC state in the latter case is prone to phase separation for moderate to strong attractiive interactions.

Figures (3)

• Figure 1: (Color online) SCOP $\Delta$ and BOP $\chi$ for $t=1$ and $n=0.3$. (a) $\Delta$ for $V=1.5$, (b) $\Delta$ for $V=2.0$, (c) $\Delta$ for $V=2.5$, (d) $\chi$ for $V=1.5$, (e) $\chi$ for $V=2.0$, and (f) $\chi$ for $V=2.5$.
• Figure 2: (Color online) Temperature dependences of the compressibility $\partial n/\partial \mu$ for several choices of $V$ with $t=1$ and $n=0.3$.
• Figure 3: (Color online) Temperature dependences of the compressibility $(\partial n/\partial \mu)_0$ when OPs other than the SCOP are omitted. Parameters are the same as in Fig.2.