Try this function get_nodes_by_authored_month_date('news', '2018-02')
use Drupal\node\NodeInterface;
/**
* @param string $bundle_type
* @param string $year_month
*
* @return array|int
*/
function get_nodes_by_authored_month_date($bundle_type = '' , $year_month = '') {
$full_date = date_parse_from_format('Y-m', $year_month);
//- Get number of days of month
$number_of_days_of_month = cal_days_in_month(CAL_GREGORIAN, $full_date['month'], $full_date['year']);
//- Get the timestamp of the first minute in the month
$first_minute_of_month = mktime(0, 0, 0, $full_date['month'], 1, $full_date['year']);
//- Get the timestamp of the last minute in the month
$last_minute_of_month = mktime(23, 59, 59, $full_date['month'], $number_of_days_of_month, $full_date['year']);
$query = \Drupal::entityQuery('node')
->condition('status', NodeInterface::PUBLISHED)
->condition('type', $bundle_type)
->condition('created', [$first_minute_of_month, $last_minute_of_month], 'BETWEEN')
->range(0, 10);
return $query->execute();
}