Normal-state Nernst effect from bidirectional bond density wave state in high-Tc cuprates

The role of charge order in the phase diagram of high-temperature cuprate superconductors has been recently emphasized with the experimental discovery of an incipient bidirectional charge density wave (CDW) phase in the underdoped regime. In a subset of the experiments, the CDW has been found to be accompanied by a d-wave intra-unit-cell form factor, indicating modulation of charge density on the oxygen orbitals sandwiched between neighboring Cu atoms on the CuO planes [the so-called bond density wave (BDW) phase]. Here we take a mean field Q(1) = (2 pi/3,0) and Q(2) = (0,2 pi/3) bidirectional BDW phase with a d-wave form factor, which closely resembles the experimentally observed charge ordered states in underdoped cuprates, and we calculate the Fermi surface topology and the resulting quasiparticle Nernst coefficient as a function of temperature and doping. We establish that, in the appropriate doping ranges where the low-temperature phase (in the absence of superconductivity) is a BDW, the Fermi surface consists of electron and hole pockets, resulting in a low-temperature negative Nernst coefficient as observed in experiments.