Stability of Charge Density Waves in Electron–Phonon Systems

With mathematical rigor, we demonstrate that electron–phonon interactions enhance the stability of charge density waves in low-temperature phases of many-electron systems. Our proof method involves an appropriate application of the Pirogov–Sinai theory to electron–phonon systems. Combining our findings with existing results, we obtain rigorous information regarding the low-temperature phase diagram for half-filled electron–phonon systems.