Topological Sachdev-Ye-Kitaev Model

TL;DR

This paper introduces an exactly solvable large-N model combining the SYK interaction with topological band structure, revealing interaction-driven topological phase transitions and emergent gapless fermions.

Contribution

It constructs a novel model linking SYK interactions with topological phases, demonstrating interaction-induced topological transitions and critical phenomena.

Findings

Interaction drives transition from trivial to topological insulator.

Emergence of a gapless Dirac fermion at criticality.

Stronger interactions reduce topological phase stability at finite temperature.

Abstract

In this letter we construct a large-N exactly solvable model to study the interplay between interaction and topology, by connecting Sacheve-Ye-Kitaev (SYK) model with constant hopping. The hopping forms a band structure that can exhibit both topological trivial and nontrivial phases. Starting from a topologically trivial insulator with zero Hall conductance, we show that interaction can drive a phase transition to topological nontrivial insulator with quantized non-zero Hall conductance, and a single gapless Dirac fermion emerges when the interaction is fine tuned to the critical point. The finite temperature effect is also considered and we show that the topological phase with stronger interaction is less stable against temperature. Our model provides a concrete example to illustrate interacting topological phases and phase transition, and can shed light on similar problems in physical systems.