> ## Documentation Index
> Fetch the complete documentation index at: https://docs.atomscale.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# List Target Materials

> Retrieve target materials with their layer stacks

Returns the target materials for your organization. A target material is the intended layer stack and substrate for a sample. Each entry describes one layer of a material, including its composition and crystallographic details.

## Response

Returns an array of target material objects. Key fields shown below (the full response includes additional metadata fields).

<ResponseField name="id" type="integer">
  Target material record ID
</ResponseField>

<ResponseField name="sample_id" type="integer">
  ID of the associated target material sample
</ResponseField>

<ResponseField name="sample_name" type="string">
  Name of the target material sample
</ResponseField>

<ResponseField name="substrate" type="string">
  Substrate the layers are grown on (e.g., `Si`)
</ResponseField>

<ResponseField name="layer_id" type="integer">
  Layer position within the stack
</ResponseField>

<ResponseField name="composition_string" type="string">
  Chemical composition of the layer (e.g., `BaTiO3`)
</ResponseField>

<ResponseField name="element_dict" type="object">
  Element counts or fractions that make up the layer
</ResponseField>

<ResponseField name="orientation" type="string">
  Crystallographic orientation of the layer, if known
</ResponseField>

<ResponseField name="space_group" type="string">
  Space group of the layer, if known
</ResponseField>

<ResponseField name="mp_id" type="string">
  Materials Project ID for the layer material, if matched
</ResponseField>

<ResponseField name="detail_notes_id" type="string">
  ID of the linked detail note, if any
</ResponseField>

<ResponseField name="detail_note_content" type="string">
  Free-text content of the linked detail note
</ResponseField>

<ResponseField name="sample_metadata" type="object">
  Arbitrary metadata attached to the target material sample
</ResponseField>

<ResponseField name="user_id" type="string">
  ID of the user who owns the record
</ResponseField>

<ResponseField name="user_name" type="string">
  Name of the user who owns the record
</ResponseField>

<ResponseField name="version" type="string">
  Schema version of the record
</ResponseField>

<ResponseField name="last_updated" type="string">
  ISO 8601 timestamp of the last update
</ResponseField>

<RequestExample>
  ```python Python theme={null}
  import requests

  response = requests.get(
      "https://api.atomscale.ai/target-materials/",
      headers={"X-API-KEY": "YOUR_API_KEY"}
  )
  target_materials = response.json()
  ```

  ```bash cURL theme={null}
  curl "https://api.atomscale.ai/target-materials/" \
    -H "X-API-KEY: YOUR_API_KEY"
  ```
</RequestExample>

<ResponseExample>
  ```json 200 theme={null}
  [
    {
      "id": 42,
      "sample_id": 42,
      "sample_name": "BaTiO3 on Si",
      "substrate": "Si",
      "layer_id": 1,
      "composition_string": "BaTiO3",
      "element_dict": { "Ba": 1, "Ti": 1, "O": 3 },
      "orientation": "001",
      "space_group": "P4mm",
      "mp_id": "mp-5020",
      "detail_notes_id": null,
      "detail_note_content": null,
      "sample_metadata": {},
      "user_id": "user_abc123",
      "user_name": "Jane Researcher",
      "version": "0.269.1",
      "last_updated": "2024-01-15T11:00:00Z"
    }
  ]
  ```
</ResponseExample>