Systems and methods for generating phase diagrams for metastable material states

Abstract

A system can include one or more processors configured to access at least one parameter of a material, generate a plurality of structures of the material using the at least one parameter, determine a state of each structure of the plurality of structures using the at least one parameter, determine a difference between the state of each structure of the plurality of structures and a ground state value, evaluate a convergence condition responsive to determining the difference between the state of each structure of the plurality of structures and the ground state value, and output at least one structure of the plurality of structures responsive to the convergence condition being satisfied.

1 . A method for generating phases for metastable states of materials, comprising:
 accessing, by one or more processors, at least one parameter of a material;   generating, by the one or more processors, a plurality of structures of the material using the at least one parameter;   determining, by the one or more processors, a state of each structure of the plurality of structures using the at least one parameter;   determining, by the one or more processors, a difference between the state of each structure of the plurality of structures and a ground state value;   evaluating, by the one or more processors, a convergence condition responsive to determining the difference between the state of each structure of the plurality of structures and the ground state value; and   outputting, by the one or more processors, at least one structure of the plurality of structures responsive to the convergence condition being satisfied.   
     
     
         2 . The method of  claim 1 , wherein outputting the at least one structure comprises generating, by the one or more processors, a phase diagram data structure representing the at least one structure. 
     
     
         3 . The method of  claim 2 , further comprising applying, by the one or more processors, a classifier to the phase diagram data structure to determine one or more boundaries between phases of the phase diagram data structure. 
     
     
         4 . The method of  claim 1 , wherein the at least one parameter comprises at least one of a temperature, a pressure, or a composition of the material. 
     
     
         5 . The method of  claim 1 , wherein the state of each structure comprises an enthalpy of the structure, and determining the state of each structure comprises providing, by the one or more processors, the structure of the material and the at least one parameter of the material as input to a density functional theory model. 
     
     
         6 . The method of  claim 1 , further comprising modifying, by the one or more processors, the plurality of structures by applying, by the one or more processors, a genetic function to the plurality of structures. 
     
     
         7 . The method of  claim 1 , comprising modifying, by the one or more processors, one or more first structures of the plurality of structures of the material responsive to the convergence condition not being satisfied. 
     
     
         8 . The method of  claim 7 , further comprising wherein modifying the one or more first structures comprises applying, by the one or more processors, a genetic operation to the one or more first structures. 
     
     
         9 . The method of  claim 7 , further comprising:
 assigning, by the one or more processors, a selection score to each of the one or more first structures based on a respective state of the one or more first structures; and   modifying, by the one or more processors, each of the one or more first structures based on the selection score assigned to the corresponding one or more first structures.   
     
     
         10 . The method of  claim 1 , wherein a threshold of the convergence condition based on which the difference between the state of each structure of the plurality of structures and the ground state value is evaluated is greater than 10 meV/atom and less than 1 eV/atom. 
     
     
         11 . A method, comprising:
 generating, by one or more processors, a plurality of candidate structures of a material;   determining, by the one or more processors, an enthalpy of each candidate structure of the plurality of candidate structures;   comparing, by the one or more processors, the enthalpy of each candidate structure to an energy threshold;   selecting, by the one or more processors, a subset of the plurality of candidate structures, each candidate structure of the subset having an enthalpy less than the energy threshold;   determining, by the one or more processors, a free energy of each candidate structure of the subset of the plurality of candidate structures for a plurality of temperature-pressure value pairs;   determining, by the one or more processors, at least one boundary between phases represented by the subset of the plurality of candidate structures; and   generating, by the one or more processors, a phase diagram data structure using the free energy of each candidate structure of the plurality of candidate structures and the at least one boundary.   
     
     
         12 . The method of  claim 2 , further comprising retrieving, by the one or more processors from the phase diagram data structure, a temperature and a pressure for controlling a process to synthesize the material. 
     
     
         13 . The method of  claim 2 , wherein the phase diagram data structure indicates a phase of the material for a particular free energy or range of free energies. 
     
     
         14 . The method of  claim 7 , wherein modifying the one or more first structures comprises modifying at least one of a bond, a bond length, an atom, or a group of atoms of the one or more first structures. 
     
     
         15 . The method of  claim 1 , wherein the state comprises at least one of enthalpy or free energy. 
     
     
         16 . The method of  claim 11 , further comprising retrieving, by the one or more processors from the phase diagram data structure, a temperature and a pressure for controlling a process to synthesize the material. 
     
     
         17 . The method of  claim 11 , wherein the phase diagram data structure indicates a phase of the material for a particular free energy or range of free energies. 
     
     
         18 . The method of  claim 11 , further comprising modifying, by the one or more processors, one or more candidate structures having an enthalpy greater than the energy threshold. 
     
     
         19 . The method of  claim 11 , wherein the plurality of candidate structures comprise at least one of a chemical structure of the material or a crystal structure of the material. 
     
     
         20 . The method of  claim 11 , wherein the energy threshold is greater than 10 MeV/atom and less than 1 eV/atom.